29. Inheritance of resistance to gall midge in rice

All India Coordinated Rice Improvement Project (AICRIP), Rajendranagar, Hyderabad-30, India

Inheritance of resistance to gall midge in rice was investigated using the greenhouse screening technique where seed-box grown plants are infested with gall midge larvae. Plants are classified as resistant or susceptible on the basis of absence or presence of silver sheets. Resistant parent (RP9-4) was crossed with two susceptible parents (Sona and TN1). Another cross studied was between Ptb 21 (resistant) and Leb Mue Nahng (susceptible). Data on the reaction of parents, F\1\ and F\2\ populations are given in Table 1. The F\1\ progenies of Sona/RP 9-4 and TNI/RP 9-4 were resistant and the F\2\ populations of these crosses segregated in a ratio of 3 resistant : 1 susceptible. The results show that a single dominant gene governs resistance to gall midge in RP9-4. RP 9-4 is a derivative from the cross IR8//MTU15/Eswarakora. Eswaralkora is the resistant parent. Thus it is obvious RP9-4 inherited a singe dominant gene for resistance to gall midge from Eswarakora.

The F\1\ progenies of the cross Ptb 21/Leb Mue Nahng were susceptible and the F\2\ population segregaged in a ratio of 1 resistant: 3 susceptible. These results show that a single recessive gene controls resistance to gall midge in Ptb 21.

Table 1. Data on the reaction to gall midge of rice cultivars and F\1\ and F\2\ populations