Abstract: To efficiently use tropical hard quality protein maize (QPM) germplasm in enriching temperate QPM germplasm, improving kernel traits, and developing hard QPM hybrids, the genetic effects and heterosis of 8 QPM inbreds with different endosperm traits and their F₁ and F₂ progenies were evaluated via Griffing I diallel mating design. The hundred-kernel weight (HKW), hundred-kernel volume (HKV), endosperm modification (EM), and kernel density (KD) showed positive heterosis in F₁ and F₂ generations. EM showed differences in F₁ reciprocal crosses, indicating obvious maternal effect. Correlation analysis showed that values of HKW, HKV, EM, and KD in F₂ generation had the biggest correlation coefficients with the average parental values. Maternal effect was the main factor on HKW, HKV, and KD, while direct genetic effect was mainly on EM. Gene actions for HKW, HKV, EM, and KD were dominant, dominant, additive, and additive & dominant, respectively. Cytoplasmic effect was little for the above 4 kernel traits suggesting that kernel traits are mainly controlled by nuclear genes.

Key words: Quality protein maize, Kernel trait, Genetic effect