Resistance of F1 sorghum hybrids to the chinch bug

Dahms, R.G.; Martin, J.H.

Resistance of F1 sorghum hybrids to the chinch bug

1940

Dahms, R.G. | Martin, J.H.

The determination of the inheritance of chinch bug resistance in sorghums by measuring the injury to the plants has been impossible because of the frequent occurrence of hybrid vigor in the plants, which enables them to escape serious injury. Chinch bugs confined on the stems of field-grown plants of susceptible sorghum varieties by means of small celluloid cages laid more eggs than those similarly confined on resistant varieties. Egg counts thus obtained offer a method for determining the genetics of resistance to chinch bug injury and for indicating in the F1 generation which crosses offer the greatest promise in breeding for resistance. When this criterion was used to measure chinch bug resistance, the data from 11 sorghum hybrids in the F1 generation and their parents indicate that in most of the crosses resistance was dominant to susceptibility. The extent of hybrid vigor as measured by height of plant, diameter of stalk, and number of tillers did not appear to be definitely associated with chinch bug resistance as measured by oviposition and longevity of the females. In general, chinch bug females lived longer on the susceptible varieties, but the difference was small, and the duration of life is a poorer criterion for measuring chinch bug resistance than is the number of eggs laid.

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