Effects of different row spacing on growth, forage yield, seed yield and its component of some grass pea (Lathyrus Sativa) variety in Sulaimani Governorate, Iraq

This study investigates the effects of varied row spacing of 20, 40, and 60 cm on three distinct grass pea (Lathyrus sativus) varieties: IF133, IF102, and IF003.The experiment was conducted at the Qlyasan Agricultural Research Station in the Sulaimani Governorate during the winter of 2022–2023 to determine the optimal row spacing and variety for grass pea development, forage yield, and yield characteristics under local climatic conditions. The study employed factorial design with three replications within a Randomized Complete Block Design (RCBD).At the effect of interaction between grass pea varieties and row spacing on growth and forage yield characters. The results showed that the variety no. 3 produced the tallest plants with (105.667 cm) when 20 cm of row spacing was used. In contrast, the interaction of 20 cm row spacing with variety no. 2 resulted in the lowest plant height with (72.633 cm). Furthermore, variety no. 3 with 20 cm row spacing produced the maximum number of days to 50% flowering reached (121.98 days),while variety no.1with40 cm row spacing produced the highest number of days to maturity (180.373days). At 40 cm row spacing variety no1 had the highest stem dry weigh reached (8.172g), while variety no.2 with 20cm row spacing had the highest dry leaf with (10.325 g).At the effect of interactions between grass pea varieties and row spacing on seed yield and its components showed that variety no.2with 40 cm row spacing had the highest harvest Index which is (0.544).While variety no. 3 recorded highest biological yield at 60 cm row spacing reached (15.224 tons/ha).