Major gene control of tolerance of bread wheat (Triticum aestivum L.) to high concentrations of soil boron

Abstract

The genetic control of tolerance of wheat to high concentrations of soil boron was studied for five genotypes. Each genotype represented one of five categories of response to high levels of boron, ranging from very sensitive to tolerant. Tolerance to boron was expressed as a partially dominant character, although the response of an F1 hybrid, relative to the parents, varied with the level of boron applied. The F1 hybrids responded similarly to the more tolerant parent at low B treatments and intermediate to the parents at higher treatments. Ratios consistent with monogenic segregation were observed for the F2 and F3 generations for the combinations (WI*MMC) × Kenya Farmer, Warigal × (WI*MMC) and Halberd × Warigal. The three genes, Bo1, Bo2 and Bo3, while transgressive segregation between two tolerant genotypes, G61450 and Halberd, suggested a fourth locus controlling tolerance to boron.