Kernel number response to plant density in tropical, temperate and tropical x temperate maize hybrids

CERRUDO, D.; HERNANDEZ, M.; TOLLNAAR, M.; VEGA, C.R.C.; ECHARTE, L.

CROP SCIENCE

CROP SCIENCE SOC AMER

Lugar: Baltimore; Año: 2020 p. 381 - 390

0011-183X

Kernel set response to plant density wasexamined in terms of physiological processes underlying kernel set in temperate(Te), tropical (Tr) and temperate x tropical (TeTr) maize (Zea mays L.) hybrids. Fourfield experiments were carried out in a subtropical environment, and treatmentscombined two new and popular commercial hybrids of each group of germplasm backgroundwith five plant densities (2 to 30 plants m-2). Determinations includedplant growth rate (PGRS) and topmost ear growth rate (EGRS)during the period bracketing silking, grain yield and its components. Inall hybrids, kernel number was the main grain yield componentcontributing to grain yield variations across densities. When grown in a highyielding subtropical environment, all hybrids exhibited increased kernel numberper area with increasing plant density from 5 to 11 plants m-2. Therewas not a clear trend among groups of germplasm background in the number ofkernel set at each plant density; but distinctive physiological processesunderlying kernel number per plant (KNP) were evident, between Te and Trhybrids. Across plant densities, KNP/PGRS ratio was larger and PGRSwas lower in Te than in Tr hybrids. Larger KNP/PGRS in Te than in Trhybrids were associated with greater prolificacy al low plant density and largerEGRS. In TeTr hybrids instead, there was not a common physiologicalprocess underlying kernel set; since genotypes representing this group sharedtraits similar to those of Te and Tr genotypes.