Assessment of wheat genotypes based on culm reserves contribution to grain yield
To study the genotypic variation in terms of culm reserves to yield attributes and grain yield in wheat, twelve cultivars were used as experiment materials. Ten tillers were sampled once a week during grain filling period to determine the changes in dry weights of different parts to examine the contribution of culm reserves to yield. The results in the experiment revealed that the grain yield varied from 261 to 535 g m−2 with the mean of 419 g m−2. The higher grain yield is attributable to increased contribution of carbon assimilation measured as the changes in total dry mass and /or remobilized culm reserves. Generally, high yielding cultivars showed higher total dry mass accumulation compared to low yielding ones. They also exhibited almost unchanged leaf greenness for longer period during grain filling that indicate more contribution of current assimilation in the high yielding cultivars. Moreover, high yielders also showed higher WSCs contents in culm at milk ripe stage. Culm WSCs contents at milk ripe and maturity varied from 83 to 603 and 4 to 151 mg culm−1, respectively among the cultivars. The amount of remobilized culm WSCs varied from 26 to 556 mg culm−1. In general, contribution of culm WSCs to grain yield is higher in high yielders than in low yielders. The contribution ranged from 2 to 29% of total grain weight. In conclusion, higher contribution of both current assimilation and culm reserves results in higher grain yield of wheat grown in Bangladesh.