Necrosis in Intervarietal Crosses of Wheat

Hybrid necrosis has been observed to vary greatly in different wheat crosses. The paper records the ratios of plants with different intensity of necrosis in the F₂ generation of some crosses. The data reveal that there are at least three alleles present at Ne₁ and Ne₂ loci. The intensity of necrosis has been explained on the hypothesis that different alleles mediate different types of necrosis and the degree of necrosis depends upon the cumulative effect of various strong and weak alleles. The data from various crosses involving strong, medium and weak alleles have been discussed in the light of the proposed model.