Genetics of Resistance to Brown Planthoppers and Green Leafhoppers in Oryza sativa L.¹

Abstract

The genetics of resistance of several rice cultivars (Oryza saliva L.) to the brown planthopper, Nilaparvata o lugens (Stal), and to the green leafhopper, Nephotettix impicticeps (Ishihara), was studied in the greenhouse. Two testing techniques were developed and employed. In one, 7-day-old seedlings were infested with insects and then classified on the basis of insect injury. In the other a known number of insects were caged on tillers of 6-weekold plants and insect survival was used as the criterion for classification. The resistance of 'Mudgo,' 'Manavari CO22,' and 'Dalwa Sannam MTU15' to the brown planthopper was controlled by single dominant genes that appeared to be allelomorphic. Another cultivar, 'Karsamba Red ASD7,' possessed a single recessive gene for planthopper resistance that was either allelic or closely linked to the locus that conditions resistance in the other three cultivars. The field reaction of F 4 lines of a cross between Mudgo and a susceptible cultivar was strongly correlated with the greenhouse reaction, and aparently the same gene controlled planthopper resistance at different stages of growth. Resistance to the green leafhopper in the cultivars 'Pankhari 203,' 'ASD7,' and 'IR8' also was controlled by single genes that were nonallelic and dominant. The planthopper resistance of Mudgo, and the leafhopper resistance of Pankhari 203 were independently inherited as was the resistance of ASD7 to the two insects.

Two whitebacked planthopper resistance genes in rice share the same loci with those for brown planthopper resistance

“…'IR26', the first BPH-resistant cultivar developed by the International Rice Research Institute, carries the BPH resistance gene Bph1. The cultivar 'IR36' carries bph2 (Athwal et al, 1971). All these indicate that most resistant cultivars carry one type of resistance gene, against either WBPH or BPH.…”

“…It has previously been shown that a single BPH-resistant gene can operate against different biotypes. The dominant gene Bph1 conferred resistance to biotypes 1 and 3 (Athwal et al, 1971). Two closely linked genes, Bph3 and bph4, conferred resistance to all the four biotypes .…”

“…It was found that different species of planthoppers were overcome by the corresponding resistance genes of rice, which can even recognize different biotypes of the same insect species. Efforts have been made to collect resistance gene resources, and more than 10 resistance genes have been identified according to their reactions to different BPH biotypes and their locations on the chromosomes (Athwal et al, 1971;Lakshminarayana and Khush, 1977;Khush and Brar, 1991;Ishii et al, 1994;Huang et al, 2001;Yang et al, 2002).…”

Detection of a brown planthopper resistance gene bph4 at the same chromosomal position of Bph3 using two different genetic backgrounds of rice

“…A similar result was obtained with another recessive BPH resistance gene. The bph2 gene was first found in a cultivar ASD7 and behaved as a recessive gene in a cross of TN1/ASD7 (Athwal et al 1971). However, the studies on the resistance segregation in a large number of F 2 and F 3 progenies from crosses of ASD7/C418 and Tsukushibare/Norin-PL4, respectively confirmed the dominant nature of bph2 (Murai et al 2001, Murata et al 1998.…”

Expression of an enhancin gene from the Trichoplusia ni granulosis virus confers resistance to lepidopterous insect pests to rice

“…In the breeding of rice plants, several genes involved in resistance to hemipteran insects such as leafhoppers have been identified (Athal et al 1971;Lakshminarayama et al 1977;Siwi et al 1977;Sidhu et al 1979;Rezaul et al 1982;Ghani et al 1988;Kabir et al 1988). However, the rice genes involved in resistance to lepidopteran pests have not been identified.…”