High amylopectin in waxy maize synergistically affects seed germination and seedling vigour over traditional maize genotypes

Waxy maize grains rich in amylopectin have emerged as a popular food and industrial raw materials. Here, a set of waxy inbreds having recessive waxy1 (wx1) gene derived through marker-assisted selection (MAS), and their original versions were evaluated for germination, seed vigour index-I and vigour index-II, electrical conductivity (EC) and enzymatic activities viz., dehydrogenase (DH), esterase (EST), peroxidase (POX), superoxide dismutase (SOD) and α-amylase (AMY). Waxy inbreds under study possessed average 97.8% amylopectin compared to 72.4% in original inbreds. Waxy versions showed 15.2% more test weight, 4.3% increase in germination, 22.7% higher seed vigour index-I and 28.3% higher seed vigour index-II, respectively, over the original inbreds. Further, activity of DH, EST, POX, SOD and AMY of MAS-derived waxy inbreds was more than that of original inbreds, whereas EC was less in improved inbreds compared to originals. Amylopectin exhibited strong positive correlations (r = 0.69 to 0.97**) with seed germination, vigour index-I and -II, DH, SOD, POX, EST and AMY activity. However, amylopectin showed negative correlation of - 0.82** with EC. Seed germination and seed vigour indices were also positively correlated with all enzymatic activities (r = 0.58 to 0.92**). The analysis revealed that waxy inbreds possess better seed vigour and enzymatic activities over traditional inbreds. This is the first report of synergistic effects of wx1 gene on seed germination, vigour and enzymatic activities in maize endosperm.