Relationship between grain filling parameters and grain weight in leading wheat cultivars in the yellow and Huai Rivers Valley

The knowledge on relationship between grain weight and grain-filling parameters is important for yield potential and stability improvement of common wheat. Logistic equation was used for fitting the grain-filling dataset from 14 leading cultivars and advanced lines, sown at Anyang, Henan province in three successive seasons from 2012 to 2015. The results showed that grain weight and all grain-filling rate (GFR) related parameters were mainly influenced by genotype, while grain-filling period related parameters were mainly influenced by environment. There was significant difference on all GFR parameters including the average and the highest GFR, and those in the three periods among cultivar groups based on grain weight, showing a trend of high-grain-weight cultivar > medium-grain-weight cultivar > low-grain-weight cultivar, whereas there was no significant difference for grain-filling period related parameters among the cultivar groups. GFR, especially in the fast increase period, was the major factor that made the significant difference of grain weight among cultivars. Positive correlations between grain weight and all GFR related parameters were observed (P < 0.001), with the coefficients of 0.97 for GFR in the fast increase period and 0.90 for average GFR, whereas no significant correlations were found between grain weight and grain-filling period related parameters. Therefore, average GFR was proposed to be used in quantitative trait loci mapping to improve grain weight of wheat in the Yellow and Huai Rivers Valley.