Gene action, heterosis of agronomic traits and variable resistance to Turcicum leaf blight in sweet corn (Zea mays saccharata L.)

Abstract

Wider ranges of variation were observed for most agronomic traits both in the parents and their F₁ experimental cross combinations of sweet corn. Four hybrids SC sel 3 × SC sel 1, SC sel 2 × SC Synthetic, SC Sel 2 × SC sel 3 and SC sel 2 × MRCSC 9 recorded higher green ear yield than best standard check hybrid which ranged from 12.21 to 12.48 tons per hectare. A substantial amount of heterosis over better parent and standard checks in a favourable direction was observed for all the characters. Against the best standard check Misti, heterosis was observed only in three hybrids for GEY, two hybrids for TSS and thirteen hybrids for GFW. The EL and KRN heterosis maintained significantly positive correlation with heterosis values of different cob characters whose heterosis would uniquely describe the GEY. Thus if there is a heterosis for EL and KRN, one would expect greater heterosis for GEY. The potence ratio indicated the presence of a high degree of overdominance in most hybrids for all traits studied suggesting the traits under the control of non-additive gene effects. However, the predominance of both partial dominance and overdominance for green fodder weight, ear height and TSS reveal that these traits are governed by both additive and non-additive gene effects.