Agronomic performance of forage corn for cattle feeding in Amazonas, Peru

Corn (Zea mays) silage is an important and popular feed for dairy production in the Amazon region, so it is necessary to evaluate the agronomic performance of forage varieties of corn for cattle feeding in Amazonas. For this purpose, three corn varieties were evaluated (variety 1: Yellow Starchy Corn, variety 2: Chuska INIA 617, and variety 3: DOW 2B710), with two planting densities (density 1: 30 × 80 cm and density 2: 35 × 75 cm) and two fertilization conditions: with fertilization (F1) and without fertilization (F2). The parameters evaluated were plant height, number of leaves, leaf length and width, stem diameter, fresh forage, and dry matter. Student t-tests, correlation analysis of variables, and principal component analysis using R software version 4.1.3 were used for data analysis. The results indicated that variety 2 obtained the best values for the variables leaf width (12.33 cm) and stem diameter (3.25 cm), fresh forage (17.77 kg/m2), and dry matter (4.8 kg/m2), which would explain the directly proportional correlation found between leaf width and stem diameter with fresh forage and dry matter. The principal component analysis showed constant height and leaf length increases, and the best-evaluated parameters were associated with applying fertilizer. The variety that showed the best agronomic performance under Chachapoyas conditions was Chuska INIA 617, emerging as a potential feed for cattle.

Evaluation of selected drying models of white sapote (Casimiroa edulisL.) slices as affected by drying methods and pre-drying treatments

This investigation was performed on the drying modelling of white sapote slices that were influenced by drying methods and pre-drying treatments. The experimentation was performed by two factors: drying techniques and pre-drying treatments. The drying techniques included oven-, solar- and open sun-driers, whereas the pre-drying pretreatments were blanching, sodium metabisulfite, sodium-chloride and control. Behaviours of the drying were plotted with the moisture ratio vs time of drying, moisture content (% db) vs time of drying, and drying rate (g of water/100 g dm/hr) versus drying time (t). At the commencement of the drying progression, the drying rate was increased steadily and reduced through the advancement of drying model parameters a and n (empirical constants) and k (drying rate constant) were determined. Their combinations were optimised to suit the requirements of the minimal value of the sum of square deviation on the expected data values (model values). The models were evaluated with the regression coefficient (R2) and chi-square (χ2), resulting in values of 0.95-0.99 and 0.000132 to 0.00511, respectively. Henderson and Pabis's model demonstrated the highest coefficient R2 values (0.99) for oven-dried drying techniques. Also, the Page model gave the highest R2 value (0.99) for sodium metabisulphite pretreatments. It can be concluded that the Henderson and Pabis model is best suited for oven drying among the drying techniques. In contrast, the Page model best fits sodium metabisulphite among the pre-drying treatments. Hence, Henderson and Pabis, and Page models might describe the drying characteristics of the white sapote fruit slices based on respective drying methods and pre-drying treatments.

Livestock nutrition and feed balance on smallholder farms in Tanqua-Abergelle district, northern Ethiopia

The present study examined the livestock feed balance of smallholder farmers in Tanqua-Abergelle district of central Tigray, northern Ethiopia. Sixty livestock households were randomly selected from two farmer associations chosen systematically based on their livestock production potential. Data were collected on household characteristics, land holding, livestock ownership, feed inventory, feed supply and feed demand using household interviews (N = 60). Field feed samples were collected and representative samples analysed for dry matter content (DM), metabolizable energy (ME) and digestible crude protein (DCP). Annual DM, ME and DCP supply and demand were estimated using proper scientific procedures. Feed balance was quantified by comparing the feed demand with the supply. Data were analysed using descriptive statistics of SPSS statistical software. Crop residues, grazing lands, crop stubble and mixed hay were investigated as the major feed resources for livestock. On average, annual feed production was 3.96 tonnes DM, 30,138 MJ ME and 171 kg DCP at household level for 4.85 TLU. Crop residues contributed to 52 % of the total annual feed supply and grazing lands to 29 %. The feed requirement for maintenance of the livestock holding was estimated at 11.06 tonnes DM, 45,580 MJ ME and 253 kg DCP. The feed balance analysis estimated a 64 % deficiency of dry matter, 34 % of ME and 32 % of protein. Based on the present findings, it is clear that either the quantitative and qualitative feed supply of the livestock must be improved or the number of livestock kept in Tanqua-Abergelle district must be reduced in order to close the feed gap.

Heterotic gains, transgressive segregation and fitness cost of sweetpotato weevil resistance expression in a partial diallel cross of sweetpotato

Heterosis-exploiting breeding schemes are currently under consideration as a means of accelerating genetic gains in sweetpotato (Ipomoea batatas) breeding. This study was aimed at establishing heterotic gains, fitness costs and transgressive segregation associated with sweetpotato weevil (SPW) resistance in a partial diallel cross of sweetpotato. A total of 1896 clones were tested at two sites, for two seasons each in Uganda. Data on weevil severity (WED), weevil incidence (WI), storage root yield (SRY) and dry matter content (DM) were obtained. Best linear unbiased predictors (BLUPs) for each clone across environments were used to estimate heterotic gains and for regression analyses to establish relationships between key traits. In general, low mid-parent heterotic gains were detected with the highest favorable levels recorded for SRY (14.7%) and WED (- 7.9%). About 25% of the crosses exhibited desirable and significant mid-parent heterosis for weevil resistance. Over 16% of the clones displayed superior transgressive segregation, with the highest percentages recorded for SRY (21%) and WED (18%). A yield penalty of 10% was observed to be associated with SPW resistance whereas no decline in DM was detected in relation to the same. Chances of improving sweetpotato through exploiting heterosis in controlled crosses using parents of mostly similar background are somewhat minimal, as revealed by the low heterotic gains. The yield penalty detected due to SPW resistance suggests that a trade-off may be necessary between maximizing yields and developing weevil-resistant cultivars if the current needs for this crop are to be met in weevil-prone areas.

Salt stress affects the biomass of industrial crop Jerusalem artichoke by affecting sugar transport and metabolism

Even though Jerusalem artichoke (Helianthus tuberosus L.) has strong resistance to abiotic stresses, salinity can still reduce the biomass of Jerusalem artichoke. The purpose of this study was to elucidate the differences in the development of Jerusalem artichoke and the dynamics of sugar throughout the growth period under high (7.23-8.15 g/kg) and low (3.20-4.32 g/kg) salinity stress in the field in Jiangsu Province, China. This study confirmed that high salinity promoted the conversion of reducing sugars to non-reducing sugars (fructans) in Jerusalem artichoke tubers, but significantly reduced the biomass of Jerusalem artichoke and advanced the peak time of the dry matter accumulation of aerial parts. In addition, in the early and late stages of tuberization, the total sugar content of tubers under low salinity conditions (786 ± 8 mg/g and 491 ± 8 mg/g) was 93.3% and 1.15 times than those under high salinity conditions, respectively. Moreover, the total sugar content in stems was consistently greater under high than low salinity conditions in the same period. The accumulation rate and the amount of dry matter were significantly higher in stems than in other tissues. Therefore, the aerial parts of "Nanyu No. 1" could be harvested before mid-to-early October, and the tubers after mid-November. This study revealed the internal reasons for the decreased yield of Jerusalem artichoke under salt stress, and provided theoretical basis and guidance for the cultivation and utilization of Jerusalem artichoke in saline-alkali soil.

Planting models and deficit irrigation strategies to improve radiation use efficiency, dry matter translocation and winter wheat productivity under semi-arid regions

The dry-land farming system of China relies on plastic film mulching and natural rainfall to mitigate damage caused by drought. However, the applications of deficit irrigation modes combined with the planting models can significantly increase production of wheat, dry matter translocation and radiation use efficiency (RUE) remains unidentified. Thus, in 2016-2018, we conducted field trials that implemented four deficit irrigation modes (IJF: irrigation at jointing and flowering stages; IF: irrigation at flowering stage; IJ: irrigation at jointing stage; NI: no irrigation) under two cultivation patterns (ridge furrow rainfall harvesting system (RF); traditional flat cultivation (TF)). The results indicated that the effects of RF system with deficit irrigation (IJF: 250 mm) could significantly increase the soil moisture, and thus enhanced LAI, I_n value, IPAR, RUE, and PAR capture ratio than that of TF-NI planting. This is due to decreased canopy light transmittance (LT), reflection and penetration ratio of PAR, as a result considerable improve the biomass translocation and grain yield. Owing to the very low soil water content after the seed-filling, the LAI, IPAR, and I_n value decreased during the seed-filling under water stress, ultimately affecting the dry matter translocation efficiency. While the IJF and IF treatments provided water for reproductive growth stage, therefore, the production of wheat and RUE were significantly maximum compared with IJ and NI irrigation mode. Under the RF system with IJF, IF, and IJ treatments the grain yield increased by 81.2%, 56.8%, 45.6% and 17.2%, then that of TF-NI treatment, respectively. The highest RUE (1.93 g MJ^-1), dry-matter translocation (154.2%) and seed yield (81.2%) were obtained in the RF-IJF treatment compared with TF-NI. Therefore, the RF-IJF treatment significantly improved the earlier development and rapid plant growth, which is a suitable planting model for increasing soil moisture, LAI, RUE, DMT, and winter wheat production.

Governing taste: data, temporality and everyday kiwifruit dry matter performances

Data is essential to governing those emerging matters of concern that confront the agrifood every day. But data is no neutral intermediary. It disrupts, exposes, and creates new social, economic, political, and environmental possibilities, whilst simultaneously hiding, excluding, and foreclosing others. Scholars have become attuned to both the constitutive role of data in creating everyday worlds, and the need to develop critical accounts of the materialities, spatialities and multiplicities of data relationships. Whereas this emerging work develops insight to the capacity for data topologies to reterritorialise the spatial performances of everyday life, it has largely reduced the associated temporal dimensions to matters of fact. The effect of these performances has been to naturalize the temporal quality of speed and elide the multiple temporalities required to enact contemporary data worlds. Applying the lenses of infrastructuring, performativity and ferality, this paper explores temporality and data in the everyday worlds produced through the New Zealand kiwifruit industry's focus on dry matter. The paper argues that temporalities are deeply embedded in the kiwifruit industry's data relations. We show that while temporal data relations are critical to the industry, we also highlight ways in which those relations introduce new, potentially destabilizing performances into kiwifruit relations.

Cassava shrunken-2 homolog MeAPL3 determines storage root starch and dry matter content and modulates storage root postharvest physiological deterioration

Among the five cassava isoforms (MeAPL1-MeAPL5), MeAPL3 is responsible for determining storage root starch content. Degree of storage root postharvest physiological deterioration (PPD) is directly correlated with starch content. AGPase is heterotetramer composed of two small and two large subunits each coded by small gene families in higher plants. Studies in cassava (Manihot esculenta) identified and characterized five isoforms of Manihot esculenta ADP-glucose pyrophosphorylase large subunit (MeAPL1-MeAPL5) and employed virus induced gene silencing (VIGS) to show that MeAPL3 is the key isoform responsible for starch and dry matter accumulation in cassava storage roots. Silencing of MeAPL3 in cassava through stable transgenic lines resulted in plants displaying significant reduction in storage root starch and dry matter content (DMC) and induced a distinct phenotype associated with increased petiole/stem angle, resulting in a droopy leaf phenotype. Plants with reduced starch and DMC also displayed significantly reduced or no postharvest physiological deterioration (PPD) compared to controls and lines with high DMC and starch content. This provides strong evidence for direct relationships between starch/dry matter content and its role in PPD and canopy architecture traits in cassava.

Genotypic variations for tuber nutrient content, dry matter and agronomic traits in tetraploid potato germplasm

Nutrient deficiencies lead to various health issues and are common worldwide. Potato germplasm is a rich source of natural variations and genetic variability present in it can be exploited for developing nutrient-rich high-yielding potato varieties. In this study, variations in the yield, dry matter (DM) and mineral nutrients concentrations were evaluated in both peeled and unpeeled tubers of 243 highly diverse tetraploid potato accessions. These were raised under field conditions for two consecutive years. The germplasm studied has a wider range of variations in peeled tubers DM (13.71-27.80%), Fe (17.08-71.03 mg/kg), Zn (9.55-34.78 mg/kg), Cu (2.13-13.25 mg/kg), Mn (7.04-25.15), Ca (117.4-922.5 mg/kg), Mg (656.6-1510.6 mg/kg), S (1121.3-3765.8 mg/kg), K (1.20-3.09%), P (0.21-0.50%) and Mo (53.6-1164.0 ppb) concentrations compared to popular Indian potato varieties. Higher nutrient concentrations in whole tubers compared to tuber flesh suggest that these are present in high concentration in the tuber peripheral layers and peeling off the tubers results in the loss of nutrients. Highest loss due to peeling off the tubers was observed in Fe (35.63%) followed by Cu (22.80%), Mn (21.69%), Ca (21.27%), Mg (12.89%), K (12.75%), Zn (10.13%), and Mo (9.87%). The GCV and PCV for all the traits in peeled tubers ranged from 9.67 to 29.91%, and 13.84 to 43.32%, respectively. Several significant positive correlations were observed among the parameters and the first two principal components accounted for 39.37% of total variations. The results of this study will pave a way for the development of nutrient-rich high-yielding potato varieties.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-022-01197-1.

Performance of apical rooted cuttings of potato grown in Mollic Andosols under different nitrogen fertilization and irrigation regimes

Potato productivity (Solanum tuberosum L) is generally influenced by several factors, including water and nitrogen (N), and potato requirement for these factors varies depending on the soil type and potato variety. This research aimed to determine the performance of apical rooted cuttings of potato grown in Mollic Andosols under different nitrogen fertilization and irrigation regimes. The treatments comprised 4 irrigation regimes of 100%, 85%, 75% and 50% of the crop evapotranspiration (ETC), where ETC100% was irrigated based on water depletion in the root zone two days after full irrigation, and 4 nitrogen rates of 0 (N0), 60 (N1), 90 (N2) and 130 kg.ha⁻¹ (N3) applied in splits at 10 (40%), 30 (40%) and 50 (20%) days after planting. The results revealed that the water demand for apical rooted cuttings of potato (ETa) was on average 201.4, 302.1, 342.4 and 402.8 mm under ETC50%, ETC75%, ETC85% and ETC100%, respectively. It was observed that plant height and number of branches significantly (P < 0.001) varied under different N rates with the highest plant height (92.67 cm) and number of branches per potato plant (17) achieved when applying N3. Potato grown under full irrigation (ETC100%) with N3 produced the highest total potato tuber yield (58.28 t.ha⁻¹) and marketable tuber yield (54.21 t.ha⁻¹). The number of tubers per plant statistically reduced as the N deficit increased, with the maximum tuber number, 23, achieved under N3. It was observed that a significant Pearson correlation (r = 0.7∗∗∗) existed between tuber number and total tuber yield. The maximum harvest index (HI), 57.12 %, was obtained under ETC50% with N3, while the highest tuber dry matter, 30 %, was observed under N3. To achieve a high tuber yield from apical rooted cuttings of potato in Mollic Andosols, this study recommends an irrigation regime of ETC100% and a nitrogen rate of 130 kg.ha⁻¹.

Impact of fertilization with reducing in nitrogen and phosphorous application on growth, yield and biomass accumulation of rice (Oryza sativa L.) under a dual cropping system

The current farming system in China is heavily reliant on synthetic fertilizers, which adversely affect soil quality and crop production. Therefore, the aim of this study was to assess the effect of different nitrogen (N) and phosphorous (P) fertilizer application rate on the growth, yield, and yield components of rice cultivars in the Binyang, Beiliu and Liucheng sites of southern China in the early (March to July) and late season (August to December). The study consisted of three fertilization regimes—CK (N₀P₀); N₁₈₀P₉₀ (180 kg N + 90 kg P₂O₅ ha⁻¹) and N₉₀P₄₅ (90 kg N ha⁻¹ + 45 kg P₂O₅)—conducted at each of three different experimental sites with four cultivars (Baixang 139, Y Liangyou 1, Guiyu 9, and Teyou 582). Results showed that the leaf area index (LAI) was 38.8% found higher in Guiyu 9 compared with Baxiang at reduced fertilization (N₉₀P₄₅). N₉₀P₄₅ resulted higher dry matter production at the heading (9411.2 kg ha⁻¹) and maturity (15319.5 kg ha⁻¹) stages in Teyou 582 at Beiliu. Fertilization (N₁₈₀P₉₀) had higher effective panicle number (4,158,800 panicle ha⁻¹) and grains panicle⁻¹ (113.84 grains) compared with other treatments. Teyou 582 treated with N₉₀P₄₅ and Y Liangyou 1 treated with N₁₈₀P₉₀ improved seed setting rate average by 82.91% and 72.17% compared with other treatments at Beiliu in both seasons, respectively. N₀P₀ and N₉₀P₄₅ increased the thousand-grain weight (TGW) of Y Liangyou 1 at Binyang (27.07 g) and Liucheng (27.84 g) during the early and late seasons, respectively. In Beiliu, the N₉₀P₄₅ treatment (6611.7 kg ha⁻¹) of Teyou 582 increased grain yield compared with other treatments. Overall, our results suggested that reducing N and P at the ratio of 90:45 kg ha⁻¹ in Teyou 582 and Y Liangyou 1 could increase rice grain yield and yield components.

Influence of sowing windows and genotypes on growth, radiation interception, conversion efficiency and yield of guar

Crop growth largely depends on radiation. Radiation is the main impetus for photosynthesis and movement of photosynthates from source to sink. Therefore, identification of the optimum sowing windows and suitable cultivars for efficient utilization of radiation is of prime importance. A field study was conducted in red clay soil during 2014 and 2015 Kharif season and the treatments consisted of three genotypes and three sowing windows by using randomized complete block design with three replications. The effect of genotypes and sowing windows was found significant with respect to number of trifoliate leaves, leaf area ratio, dry matter production, grain numbers, pod length, test weight, grain yield, and stover yield of guar during 2014 as compared to 2015 sown crop. Statistically significant plant height, number of trifoliate leaves, number of branches, leaf area ratio, absolute growth rate, leaf area index, dry matter, grain number, pod length, grain yield, stover yield and a higher cumulative radiation interception were recorded with 15th August sown crop as compared to other sowing windows. The plant height, number of trifoliate leaves, number of branches, leaf area ratio, absolute growth rate, leaf area index, dry matter, grain number, pod length, grain yield, stover yield and maximum cumulative interception of radiation were significant with RGC-1003 as compared to RGC-936 and HG-365. It is observed that the incident PAR to dry matter accumulation conversion efficiency was varied with cultivars and different sowing windows which ranges from 0.74 g MJ^-1 to 0.79 g MJ^-1.

Subsoiling increases aggregate-associated organic carbon, dry matter, and maize yield on the North China Plain

Background

Soil degradation is one of the main problems in agricultural production and leads to decreases in soil quality and productivity. Improper farming practices speed this process and are therefore not conducive to food security. The North China Plain (NCP) is a key agricultural area that greatly influences food security in China. To explore the effects of different tillage measures on aggregate-associated organic carbon (AOC), the accumulation and transport of dry matter, and maize yield, and to identify the most suitable tillage method for use on the NCP, a field experiment was conducted at Shandong Agricultural University from 2016–2017 using plots that have been farmed using conservation tillage since 2002.

Methods

In this study, Zhengdan 958 summer maize was used as the test material and undisturbed soil and plant samples were obtained under four tillage methods—no-tillage (NT, tillage depth: 0 cm); rotary tillage (RT, tillage depth: 10 cm); conventional tillage (CT, tillage depth: 20 cm); subsoiling (SS, tillage depth: 40 cm)—which were used to determine the AOC and dry matter contents, as well as the yields of two summer maize growing seasons. Each sample was replicated three times and the AOC content was determined via potassium dichromate oxidation colorimetry. Potassium dichromate oxidized organic carbon in organic matter was employed to reduce hexadecent chromium into green trivalent chromium. Colorimetry was then used to determine the amount of reduced trivalent chromium and calculate the organic matter content.

Results

The resulting data were statistically analyzed and the results showed that, compared with CT, the AOC contents with NT and SS increased by 5.65% and 9.73%, respectively, while that with RT decreased by 0.12%. Conventional tillage resulted in the highest mean dry matter weight when the maize reached maturity, which was 19.19%, 9.83%, and 3.38% higher than those achieved using NT, RT, and SS, respectively. No significant difference was found between CT and SS treatments, both of which tended to increase the accumulation of dry matter as well as its contribution of assimilates to grain yield post-anthesis. Compared with CT, the mean yield increased at a rate of 0.18% with SS, while yields declined at rates of 17.17% and 11.15 with NT and RT, respectively. The yield with NT was the lowest, though the harvest indices with NT and SS were higher than those with RT and CT. Overall, SS increased the accumulation of dry matter and its contribution of assimilates to grain yields post-anthesis, as well as the AOC content and yields, making it the ideal tillage method for the NCP.

Postharvest diseases and disorders in avocado cv. Hass and their relationship to preharvest management practices

Postharvest diseases and disorders are two of the most important parameters associated with the quality of avocado fruit. The aim of this study was to identify postharvest diseases and disorders in Hass avocado plots and to evaluate their relationships with different preharvest agronomical practices. This work was developed in 20 commercial plots of Hass avocado dedicated to production for national and export markets. The first part of this work was associated with the identification and characterization of diseases and disorders related with postharvest of avocado. In addition, it was determined the incidence of each disease and disorder based on simulation of postharvest scenarios for the national and export markets. Using a multinomial logistic regression model, it was possible to determine that the presence of each disease and disorder were related to crop management practices, soil and leaf and fruit nutrients levels. Most relevant postharvest disease and disorders were anthracnose, stem-end rot, chilling injury, and lenticel damage. Additionally, variables such as dry matter, plant pruning, and tissue concentration of Ca⁺² were related with some pathologies and disorders. This work presents an advance in the recognition of postharvest diseases and disorders in avocado under tropical conditions, besides determining the main edaphic and anthropogenic associated factors.

BLUP and stability analysis of multi-environment trials of potato varieties in sub-tropical Indian conditions

Potato is an important crop in India with area spread across Himalayan hills in the North to hot tropical conditions in South, albeit major area in sub-tropical Indo-Gangetic plains. The first common requirement in all regions is that the variety should have high performance for tuber yield along with essential agronomic traits. The present study was carried out to identify an ideal variety with wide adaptability for tuber yield and dry matter. Six varieties were evaluated in 9, 11 and 10 locations in the years 2014-15, 2015-16 and 2016-17, respectively for TY, MY and DM. The data were analysed with ANOVA, mixed models, BLUPs and GGE biplot as well as univariate stability statistics. Combined analysis of variance showed significant genotype, environment and genotype × environment interactions. The relative magnitudes of G, E and G×E variances accounted for 6.76-8.91, 51.85-76.65 and 12.41-23.19 per cent for TY and 2.86-4.66, 65.87-72.85 and 13.74-20.04 per cent for DM. Although the genotypes contributed significantly, major part of the variation was explained by environments for all the three traits. Mean across locations and years, and BLUP values of varieties for all the three traits showed similar results with Kufri Khyati as the best variety for TY and MY, whereas Kufri Jyoti and Kufri Garima were best for DM. Based on GGE biplot and univariate stability statistics, Kufri Khyati was the ideal high yielding wide adaptable variety in all the three years and Kufri Jyoti was the ideal variety based on mean dry matter and stability. The environments were very diverse and their clustering suggested three groups, which can be used as three separate zones for varietal evaluation and regional deployment of varieties.

Chemical composition, fermentative characteristics, and in situ ruminal degradability of elephant grass silage containing Parkia platycephala pod meal and urea

This study aimed to evaluate the effects of the addition of Parkia platycephala pod meal (PP) and urea on the chemical composition, fermentation characteristics, and in situ ruminal degradability of elephant grass silage. A completely randomized design with a 4 × 2 factorial arrangement was adopted, with four levels of pod meal (0, 10, 20, and 30%) and two levels of urea (0 and 1.5%) on as fed basis. The produced silages were evaluated in terms of dry matter (DM), crude protein (CP), mineral matter (MM), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, ammonia nitrogen, pH, short chain fatty acids, and in situ ruminal degradability. For the study of degradation, four Santa Ines rumen fistulated sheep, with average weight of 45 ± 2.5 kg were used. The association of the additives increased (p < 0.05) DM, CP, DM degradability, fractions a, b, and effective degradability at all passage rates (2, 5, and 8%/h) and reduced NDF and ADF contents. DM disappearance increased (p < 0.05) during the incubation time, especially for the silages containing the two additives. The interaction in the rumen environment is essential for microbial multiplication. Thus, the use of additives such as PP and urea contributed to the availability of digestible fractions of the feed and greater use by ruminal microorganisms. The association of Parkia platycephala with urea improves the fermentation characteristics, chemical composition, and degradability of elephant grass silage.

Productivity and nutritional value of BRS capiaçu grass (Pennisetum purpureum) managed at four regrowth ages in a semiarid region

The objective of this study was to evaluate the productivity, productive efficiency, and nutritional value of the elephant grass cultivar BRS capiaçu (Pennisetum purpureum Schum.), managed at four regrowth ages during winter in the semiarid region of northern Minas Gerais, Brazil. A completely randomized design with the elephant grass cultivar BRS capiaçu was submitted to four cut intervals (30, 60, 90, and 120 days) in the winter with ten replications, for a total of 40 plots, each with a useful area of 6 × 5 m. There was a linear increase of 76.25% (P < 0.01) in the height of BRS capiaçu grass when cut from 30 to 120 days. Green matter production (P < 0.01) and dry matter production (P < 0.01) increased daily by 1081 kg/ha and 237 kg/ha, respectively. The annual dry matter production was 72 t/ha. Efficiency in water use changed (P < 0.01) from 7.91 kg of dry matter (DM)/mm at 30 days to 57.59 kg of DM/mm at 120 days of regrowth. There was a reduction in the ash content (P < 0.01), crude protein (P < 0.01), and the total digestible nutrient content (P < 0.01) with the increase in the age of the cut. The readily soluble fraction of DM (fraction A, P < 0.01), degradation rate "c" of insoluble fraction "B" (P = 0.01), potential degradability (PD; P < 0.01), and degradability (ED; P < 0.01) decreased linearly as the regrowth age increased. Harvesting is recommended at 90 days of regrowth during the winter season in this semiarid region.

Apoplasmic and simplasmic phloem unloading mechanisms: Do they co-exist in Angeleno plums under demanding environmental conditions?

Biophysical fruit growth depends on a balance among the vascular and transpiration flows entering/exiting the fruit via phloem, xylem and through the epidermis. There is no information on vascular flows of Japanese plums, a species characterized by high-sugar content of its fruit at harvest. Vascular flows of Angeleno plums were monitored by fruit gauges during late fruit development, under the dry environment of the Goulburn Valley, Victoria, Australia. Phloem, xylem flows and skin transpiratory losses were determined, as well as diurnal leaf, stem and fruit pressure potentials. Fruit seasonal development, skin conductance and dry matter accumulation were also monitored. Fruit grew following a double-sigmoid pattern, but fruit size increased only 3.1 g over the last 3 weeks of development. Fruit grew very little in the morning, primarily due to phloem inflows (0.05 g fruit^-1hr^-1), while water left the fruit via the xylem. Negligible skin transpiration was recorded for vapour pressure deficit (VPD) values below 3 kPa. This growth pattern, in the absence of skin transpiration, suggests apoplastic phloem unloading. However, at VPD values over 3 kPa (e.g. from early afternoon to a peak around 18:00 h), transpiratory losses through the skin (up to 0.25 g fruit^-1hr^-1) caused fruit to shrink, leading to enhanced phloem and xylem inflows (ca. 0.15 g fruit^-1hr^-1), a scenario that would correspond to symplastic phloem unloading. Over 24 h the fruit showed a slightly negative total growth, consistent with fruit growth measured in situ during the season at weekly intervals. A few fruit species are known to alter their phloem unloading mechanism, switching from symplastic to apoplastic during the season. Our data support the coexistence in Japanese plum of different phloem unloading strategies within the same day.

Real-time, non-destructive and in-field foliage yield and growth rate measurement in perennial ryegrass (Lolium perenne L.)

BACKGROUND

In-field measurement of yield and growth rate in pasture species is imprecise and costly, limiting scientific and commercial application. Our study proposed a LiDAR-based mobile platform for non-invasive vegetative biomass and growth rate estimation in perennial ryegrass (Lolium perenne L.). This included design and build of the platform, development of an algorithm for volumetric estimation, and field validation of the system. The LiDAR-based volumetric estimates were compared against fresh weight and dry weight data across different ages of plants, seasons, stages of regrowth, sites, and row configurations.

RESULTS

The project had three phases, the last one comprising four experiments. Phase 1: a LiDAR-based, field-ready prototype mobile platform for perennial ryegrassrecognition in single row plots was developed. Phase 2: real-time volumetric data capture, modelling and analysis software were developed and integrated and the resultant algorithm was validated in the field. Phase 3. LiDAR Volume data were collected via the LiDAR platform and field-validated in four experiments. Expt.1: single-row plots of cultivars and experimental diploid breeding populations were scanned in the southern hemisphere spring for biomass estimation. Significant (P < 0.001) correlations were observed between LiDAR Volume and both fresh and dry weight data from 360 individual plots (R² = 0.89 and 0.86 respectively). Expt 2: recurrent scanning of single row plots over long time intervals of a few weeks was conducted, and growth was estimated over an 83 day period. Expt 3: recurrent scanning of single-row plots over nine short time intervals of 2 to 5 days was conducted, and growth rate was observed over a 26 day period. Expt 4: recurrent scanning of paired-row plots over an annual cycle of repeated growth and defoliation was conducted, showing an overall mean correlation of LiDAR Volume and fresh weight of R² = 0.79 for 1008 observations made across seven different harvests between March and December 2018.

CONCLUSIONS

Here we report development and validation of LiDAR-based volumetric estimation as an efficient and effective tool for measuring fresh weight, dry weight and growth rate in single and paired-row plots of perennial ryegrass for the first time, with a consistently high level of accuracy. This development offers precise, non-destructive and cost-effective estimation of these economic traits in the field for ryegrass and potentially other pasture grasses in the future, based on the platform and algorithm developed for ryegrass.

Multiple linear regression modeling: Prediction of cheese curd dry matter during curd treatment

Cheese curd dry matter determines functional properties and process parameters during cheese manufacture. Dry matter is affected by many internal (milk composition and pre-treatment) and external (cheese process parameters) factors that are not considered in the most common models. The purpose of this study was to consider a large number of multiple linear regression models that use these internal and external factors as predictor variables, and select the most suitable of these models in order to predict the cheese curd dry matter during curd treatment. Dry matter (DM_exp,nat) was experimentally determined to create a native data set (n = 1013) for fitting the regression model. Dry matter was affected by curd treatment time (CTT), curd treatment temperature (ϑ), pH-value (pH), curd grain size (CGS), fat level (f) and degree of microfiltration (i). A large number of empirical regression models, organized into three different groups, depending on the predictors used, were developed on basis of DM_exp,nat. A Monte Carlo approach was used to select the optimal model, taking into account the value of Akaike's information criterion (AICc) and the coefficient of determination (R²) of each model. The best models were further analyzed to check for potential bias and to verify that the model assumptions were met. We considered one model of group G2 with 11 terms to most closely fit the aforementioned criteria (native data set; R² = 95.55). This model was successfully validated by an independent validation data set (n = 120; R² = 91.95).

Balance between salt stress and endogenous hormones influence dry matter accumulation in Jerusalem artichoke

Salinity is one of the most serious environmental stresses limiting agricultural production. Production of Jerusalem artichoke on saline land is strategically important for using saline land resources. The interaction between plant hormones and salinity stress in governing Jerusalem artichoke (Helianthus tuberosus) growth is unclear. Jerusalem artichoke (variety Nanyu-1) was grown under variable salinity stress in the field, and a role of endogenous hormones [zeatin (ZT), auxins (IAA), gibberellins (GA3) and abscisic acid (ABA)] in regulating sugar and dry matter accumulation in tubers was characterized. Under mild salt stress (≤2.2gNaClkg(-1) soil), Nanyu-1 grew well with no significant alteration of dry matter distribution to stems and tubers. In contrast, under moderate salt stress (2.7gNaClkg(-1) soil), the distribution to stem decreased and to tubers decreased significantly. Mild salt stress induced sugar accumulation in tubers at the beginning of the tuber-expansion period, but significantly inhibited (i) transfer of non-reducing sugars to tubers, and (ii) polymerization and accumulation of fructan during the tuber-expansion stage. Under different salinity stress, before the stolon growth, the ratio of IAA/ABA in leaves increased significantly and that of GA3/ABA increased slightly; during tuber development, these ratios continued to decrease and reached the minimum late in the tuber-expansion period. While, salt stress inhibited (i) underground dry matter accumulation, (ii) tuber dry matter accumulation efficiency, (iii) transport of non-reducing sugars to tubers, and (iv) fructan accumulation efficiency during the tuber-expansion period; these effects were accompanied by significantly decreased tuber yield with an increase in salinity. With soil salinity increasing, the synthesis of IAA and GA3 was inhibited in leaves and tubers, while ABA synthesis was stimulated. In brief, tuber yield would significantly decreased with the increase of salinity.

Himalayan dock (Rumex nepalensis): the flip side of obnoxious weed

Himalayan dock (Rumex nepalensis) was evaluated for forage value and antinutrients under three, five and seven weeks cutting intervals in the temperate environment. Dry matter (DM) content was measured for each cutting interval. Forage quality parameters such as Crude Protein (CP), Acid Detergent fiber (ADF), Neutral Detergent Fiber (NDF), Calcium (Ca) and Phosphorus (P) were analyzed. Plants with seven weeks cutting interval gave higher DM yield. CP and P content were significantly higher for three weeks cutting intervals. Average CP contents were 31.38 %, 30.73 % and 27.32 % and average P content 0.58 %, 0.52 % and 0.51 % for three, five and seven weeks cutting intervals, respectively. Ca content did not differ significantly between cutting intervals. The average Ca content were 0.91 %, 0.90 % and 90 %, for three, five and seven weeks cutting intervals, respectively. Tannin and mimosine contents were not significantly different between cutting intervals. Average tannin contents were 1.32 %, 1.27 % and 1.26 % and mimosine 0.38 %, 0.30 % and 0.28 % for three, five and seven weeks cutting intervals, respectively. The study concluded that R. nepalensis could be a potential source of protein for livestock. The study also suggests seven weeks harvesting interval to provide plants with high dry matter yield, high forage quality and very low levels of anti-nutrients.

Towards on-line prediction of dry matter content in whole unpeeled potatoes using near-infrared spectroscopy

Prediction of dry matter content in whole potatoes is a desired capability in the processing industry. Accurate prediction of dry matter content may greatly reduce waste quantities and improve utilization of the raw material through sorting, hence also reducing the processing cost. The following study demonstrates the use of a low resolution, high speed NIR interactance instrument combined with partial least square regression for prediction of dry matter content in whole unpeeled potatoes. Three different measuring configurations were investigated: (1) off-line measurements with contact between the potato and the light collection tube; (2) off-line measurements without contact between the potato and the light collection tube; and (3) on-line measurements of the potatoes. The offline contact measurements gave a prediction performance of R(2)=0.89 and RMSECV=1.19. Similar prediction performance were obtained from the off-line non-contact measurements (R(2)=0.89, RMSECV=1.23). Significantly better (p=0.038) prediction performance (R(2)=0.92, RMSECV=1.06) was obtained with the on-line measuring configuration, thus showing the possibilities of using the instrument for on-line measurements. In addition it was shown that the dry matter distribution across the individual tuber could be predicted by the model obtained.

Quality and chemical composition of ten red raspberry (Rubus idaeus L.) genotypes during three harvest seasons

Colour and chemical composition of fruits of 10 red raspberry genotypes grown in Nordic climate during three harvest seasons were studied. The main phenolic compounds in the fruits were ellagitannins and anthocyanins, contributing 57% and 42% to the quantified phenolic compounds, respectively. Cyanidin-3-sophoroside was the most abundant anthocyanin (61%). All quality parameters were significantly affected by genotype. The genotypes could be categorised into three groups. 'Veten' and 'RU984 06038' were characterised by high concentrations of flavonoids, i.e., anthocyanins and quercetin glycosides, and dark red colour. 'Octavia', 'Glen Magna', 'RU004 03067', 'Glen Ample' and 'RU974 07002' were characterised by light colour, high titratable acids and low flavonoid concentrations. 'Malling Hestia', 'RU024 01003' and 'RU004 04095' had high content of dry matter, soluble solids, ascorbic acid and ellagic acid containing compounds, in addition to high hue and chroma values. All quality parameters, except ascorbic acid and lambertianin C, varied significantly between harvest seasons. The lowest seasonal variation in fruit quality was observed in 'RU024 01003' and 'Glen Ample' and the highest 'RU004 03067' and 'Glen Magna'.

Rapid phenotyping of the tomato fruit model, Micro-Tom, with a portable VIS-NIR spectrometer

Tomato (Solanum lycopersicum) quality traits such as juice soluble solid content (Brix), juice pH, color parameters (Hue and Chroma), firmness and water content, are critical factors for fruit quality assessment. The need for screening very large numbers of fruit has led to the development of a high-throughput method using visible-near infrared (VIS-NIR) spectrometry. We are reporting here a set of results obtained with a portable spectrometer using the 350-2500 nm range, showing good prediction of the quality traits cited above, over a wide range of developmental stages from immature green to ripe tomato fruit, cv. Micro-Tom. This is a rather good set of quality traits compared to previous publications predicting tomato quality with VIS-NIR spectrometry, and the prediction is robust, as it was obtained by grouping sets of different operators. This would be a useful tool to phenotype hundreds of Micro-Tom per day, making it possible to follow the dynamics of the described parameters on growing fruits. Thus the method can be used to study the biochemistry and physiology of fruit development in planta.