Mechanism of pod shattering in the forage legume Medicago ruthenica

Seed quality as a proxy of climate-ready orphan legumes: the need for a multidisciplinary and multi-actor vision

In developing countries, orphan legumes stand at the forefront in the struggle against climate change. Their high nutrient value is crucial in malnutrition and chronic diseases prevention. However, as the 'orphan' definition suggests, their seed systems are still underestimated and seed production is scanty. Seed priming is an effective, sustainable strategy to boost seed quality in orphan legumes for which up-to-date guidelines are required to guarantee reliable and reproducible results. How far are we along this path? What do we expect from seed priming? This brings to other relevant questions. What is the socio-economic relevance of orphan legumes in the Mediterranean Basin? How to potentiate a broader cultivation in specific regions? The case study of the BENEFIT-Med (Boosting technologies of orphan legumes towards resilient farming systems) project, developed by multidisciplinary research networks, envisions a roadmap for producing new knowledge and innovative technologies to improve seed productivity through priming, with the long-term objective of promoting sustainability and food security for/in the climate-sensitive regions. This review highlights the existing drawbacks that must be overcome before orphan legumes could reach the state of 'climate-ready crops'. Only by the integration of knowledge in seed biology, technology and agronomy, the barrier existing between research bench and local agricultural fields may be overcome, generating high-impact technical innovations for orphan legumes. We intend to provide a powerful message to encourage future research in line with the United Nations Agenda 2030 for Sustainable Development.

Analysis of seed production and seed shattering in a new artificial grassland forage: pigeon pea

Pigeon pea is a perennial leguminous plant that is widely cultivated as a forage and pharmaceutical plant in subtropical and tropical areas, especially in artificial grasslands. Higher seed shattering is one of the most important factors in potentially increasing the seed yield of pigeon pea. Advance technology is necessary to increase the seed yield of pigeon pea. Through 2 consecutive years of field observations, we found that fertile tiller number was the key component of the seed yield of pigeon pea due to the direct effect of fertile tiller number per plant (0.364) on pigeon pea seed yield was the highest. Multiplex morphology, histology, and cytological and hydrolytic enzyme activity analysis showed that shatter-susceptible and shatter-resistant pigeon peas possessed an abscission layer at the same time (10 DAF); however, abscission layer cells dissolved earlier in shattering-susceptible pigeon pea (15 DAF), which led to the tearing of the abscission layer. The number of vascular bundle cells and vascular bundle area were the most significant negative factors (p< 0.01) affecting seed shattering. Cellulase and polygalacturonase were involved in the dehiscence process. In addition, we inferred that larger vascular bundle tissues and cells in the ventral suture of seed pods could effectively resist the dehiscence pressure of the abscission layer. This study provides foundation for further molecular studies to increase the seed yield of pigeon pea.