Peanut FAD2 Genotype and Growing Location Interactions Significantly Affect the Level of Oleic Acid in Seeds

Understanding variation in oleic acid content of high-oleic virginia-type peanut

Contamination at the FAD2B locus due to inadequate screening protocols is the primary cause of sporadic, insufficient oleic acid content in Virginia-type peanut. The high oleic trait in peanut is conditioned by loss-of-function mutations in a pair of homeologous enzymes and is well known to improve the shelf life of peanut products. As such, the trait is given high priority in current and future cultivars by the North Carolina State University peanut breeding program. For unknown reasons, high oleic cultivars and breeding lines intermittently failed to meet self-imposed thresholds for oleic acid content in internal testing. To determine why, a manual seed chipper, crude DNA isolation protocol, genotyping assays for both mutations, and a web-based SNP calling application were developed. The primary cause was determined to be contamination with normal oleic seeds resulting from inadequate screening protocols. In order to correct the problem, a faster screening method was acquired to accommodate a higher oleic acid threshold. Additionally, results showed the mutation in one homeolog is fixed in the program, dig date had no significant effect on oleic acid content, and minor modifiers segregating within the program explained 6% of the variation in oleic acid content.

Optimizing sowing date for peanut genotypes in arid and semi-arid subtropical regions

Peanut (Arachis hypogea L.) is an important nut crop extensively grown in rainfed regions of Pakistan. The crop requires low inputs; thus, could grow successfully under diverse environmental conditions. Due to pegging ability, peanut grows aggressively in sandy and sandy-loam soils. However, it has not introduced to Thal region of southern Punjab, Pakistan. A two-year field experiment was conducted to optimize sowing dates for two peanut genotypes ('BARI-2016' and 'NO-334') in Thal region (Layyah). Similarly, a yield trial was conducted at Chakwal where both genotypes are extensively grown. Five sowing dates (10th April, 1st May, 20th May, 10th June and 30th June) were included in the study. The highest seed yield was obtained with early sown crop (10th April) during both years. Pod formation reduced with increasing atmospheric temperature and no pods were formed on the plants sown on 30th June. Decreased pod formation seemed a major reason for low yield in late-sown crop. The highest yield was observed for the crop sown on 10th April, which was decreased by 40% for the crop sown on 1st May. Genotype 'BARI-2016' performed better for seed yield at both locations compared with 'NO-334'. The results suggested that genotype 'BARI-2016' is more adaptive to arid and semi-arid condition under rainfed or irrigated conditions. Sowing peanut at optimum time would increase seed yield in arid and semi-arid regions. Nonetheless, 'BARI-2016' can be grown under rainfed and irrigated conditions successfully.