Oil and Protein Accumulation in Soybean Grains under Salinity Stress

Abstract

Two factorial experiments based on randomized complete block design (RCBD) with three replications were conducted in 2007 and 2008, to evaluate grain development (four harvests) and rate and duration of oil and protein accumulation in three soybean cultivars (‘Williams’, ‘Zan’ and ‘L17’) under a non-saline (control) and three saline (3, 6 and 9 ds/m NaCl) conditions. Six seeds were sown in each pot filled with 900 g perlite, using 144 pots for each experiment. After emergence, seedlings were thinned and 4 plants were kept in each pot. Rate of oil accumulation up to maturity was not significantly affected by salinity. With increasing salinity, rate and percentage of protein accumulation, duration of oil and protein accumulation and oil and protein content per grain decreased, but oil percentage increased. Oil and protein yields per plant decreased as salinity increased. These reductions were mainly attributed to the short duration of protein and oil accumulation and grain yield per plant under saline conditions. ‘Williams’ had the highest rate and duration of protein accumulation and rate of oil accumulation, but ‘L17’ had the highest grain yield per plant. Consequently, differences in protein and oil yields per plant between these two cultivars were not statistically significant. However, ‘Zan’ had the lowest protein and oil yields, due to the lowest grain yield per plant.