Effect of Planting Date, Variety and their Interaction on Seed Yield and its Components of Egyptian Clover (Trifolium alexandrinum L.)

This investigation was carried out to study the effect of temperature resulting from different planting dates during the stage of flowering and seed maturity and the effect of genotypes x environment interaction on seed yield and its components in some varieties of berseem clover (Trifolium alexandrinum L.). A set of six varieties (Serw-1, Gemmeiza 1, Giza-6, Sakha-4, Helally and Local variety) were sown on four planting dates (September 15^th, October 15^th, November 15^th and December 15^th) in randomized complete block design with four replicates for each planting date. Three cuts were taken after 70, 110, 145 days from sowing. The experiments were conducted during 2014/2015 and 2015/2016 seasons in experimental farm of Assiut University. Results revealed that the highest number of seeds/ inflorescence (48.1), seed setting (72.8%), 1000 seed weight (3.21 g) and seed yield (1.25 kg/plot) were obtained from sowing on the 15^th September. This result due to seed production is taking place during the period from April to the Mid-June.
The Sakha-4 variety outyielded (1.07 kg/plot) other tested varieties. On the other hand, the local variety gave lowest yield (0.90 kg/plot) over all planting dates and seasons. The estimates of genotypic stability parameters (a and l) for seed yield showed that variety Sakha-4 was the highest seed yielding, but exhibited less stability (instable) in seed yield. While Helally and Serw-1 varieties were more stable. On the other hand, local variety showed lower seed yield and instability.