Heterosis Of Starch Viscosity And Correlation With Main Traits In Waxy Corn

Ten inbreds and their fifty hybrids by p+q+2pq genetic design were experimented to analyse the heterosis of starch viscosity characters and the correlation with main traits in waxy corn. The results showed as follows:(1) There were significant differences in starch viscosity characters of parents and their hybrids. And the differences in hybrids were wider than in parents.(2) Heterosis of seven starch viscosity characters were that over-MP heterosis in Breakdown (BD) , over-LP heterosis in Peak Viscosity (PV) and Setback(SB), no heterosis in Trough Viscosity (TV), Final Viscosity (FV), Peak time (PT) and Pasting Temperature (PTP). PV, TV, BD and SB of the hybrids were significantly correlative with that of their female and middle of parents, while FV, PT and PTP of the hybrids were not.(3) Starch viscosity characters were controlled by maternal plant genotypes and no genetic segregation occurred in F2 grains. And cytoplasm effect was tested in all starch RVA characters. PV, TV, BD, FV and SB had relatively high broad heritability, while PT and PTP had relatively low broad heritability. The narrow heritability of starch viscosity characters was also very high except that of SB, PT and PTP. Additive effect was the main factor of genetic variance for TV and FV. Both additive and dominance effect were almost equally important factors of genetic variance for PV, PTP, SB, and PT. Dominance effect was the main factor of genetic variance for BD.(4) The general combining ability (GCA) of ten parents were that parent D was the highest in PV and BD, parent 4 in TV, parent B in FV, parent 3 in SB, PT and PTP by positive crossing (1, 2, 3, 4, 5 as female parent and A, B, C, D, E as male parent), while parent 4 in PV and BD, parent 5 in TV and FV, parent 3 in SB, PT and PTP by anti crossing(l, 2, 3, 4, 5 as male parent and A, B, C, D, E as female parent).The special combining ability (SCA) were that 3×A was the highest in PV, TV and BD, 5×B in FV, 3×E in SB, 3×C in PT, 1 ×D in PTP by positive crossing, while the SCA of E×3 was the highest in PV, TV and FV, E×4 in BD, C×1 in SB, D×5 in PT, B×1 in PTP by anti crossing.(5) Starch viscosity characters with relation to main traits were that significant negative correlation (P0.01) were between FV, SB, PT, PTP and grain oil content, between TV and row kernel number, between PTP and ear row number, significant positive correlation (P0.01) were between SB and yield, ear length, between PV, BD and grain oil content, between PTP and grain protein content.