Genotype-sowing date interaction in soybean in Western Saudi Arabia

الملخص EN

-The photoperiodic response of soybean [Glycine max (L) Merr .] is a major factor determining tlie latitude and the sowing date at which soybean cultivars are grewn.

In or der to elucida te the effect of sowing da te o n phen ot ypic perform ance and stability of soybean, 16 geno types of diver se origin were grown in thr ee different seasons: summer , fall and winter in a randomized compl ete block design exper iment with thr ee repl ications.

Data record ed on days to 50% flowering , plant height , seed size , harvest index (HI) and seed yield in each season as well as over the thre e seasons were analyzed and the differ ent variance components were obtained .

Stabilit y param et ers were also estimate d for seed yield and HI.

Sowing date effe cts and sowing date-g enotype interactions wer e found to be highly significant for all trait s mean while genot ype effects were found to be significant for plant height and 100 seed weight.

Seed yield showed to be more stable than HI and this could be due to the dependence of seed yield on diver se source of assimilates.

November sown cult ivar s had moderate HI but they were significantlyshort er, and had significantly larger seed size and higher seed yield than May and Sept ember sown cultivars.

Cultivars Jupi ter, ICAL 124 and Alamo proved to be stable and are considere d to be best suited for the region