Source and sink traits and their relationship under deficit soil moisture stress conditions in an indeterminate crop: sesame (Sesamum indicum L.)

ABSTRACTSesame is an indeterminate oilseeds crop where yield is a cumulative effect of source and its capacity for synthesis and mobilization of photosynthates. Knowledge of the existing relation between source and sink and its validation under deficit soil moisture conditions is limited in sesame. Therefore, experiments were conducted using twenty five sesame genotypes of differing for their plant architecture in terms of branching pattern (mono to multiple) and leaf area (minimum to maximum) under both irrigated (IR) and deficit moisture stress (DS) conditions for two consecutive years 2021 and 2022. The variations existing among the source and sink traits were measured and analysis of variance of the measured traits revealed a significant differences among the genotypes for source traits viz. leaf area, stem & leaf dry weight, net photosynthesis, total dry matter and their relationship with sink i.e. seed yield under IR and DS conditions and it was conformed using regression analysis. The results showed that source traits such as stem dry weight and total dry matter at the seed filling stage were positively associated with seed yield at both IR and DS conditions. Additionally, cluster analysis showed that the genotypes IC 54039-B-1 and SI 1802 had proportional leaf area with good seed yield and displayed a better source and sink relationship, highlighting the fact that photosynthates were efficiently translocated to the sink. The genotypes IC 54039-B-1 and SI 1802 outperformed IR under DS with minimal yield differences and optimal leaf weight, total dry matter, and plant stem weight. These genotypes with better source and sink relationships can be used in sesame crop improvement programmes