these major genes (Gallagher et al., 1994;Ketipearachchi et al., 1998). It has long been suggested that quantita-The brown planthopper (BPH), Nilaparvata lugens (Stå l) (Homotive resistance should be more durable (Heinrichs, 1986; ptera: Delphacidae), is one of the major insect pests of rice (Oryza sativa L.). Many major genes are now available to manage this pest Bosque-Perez and Buddenhagen, 1992). Until recently, through host-plant resistance. In this study, we mapped quantitative the genetic basis of quantitative resistance to insect pests trait loci (QTLs) associated with resistance to BPH using a doubled could not be explained owing to the inherent complexity haploid (DH) population derived from the cross IR64/Azucena. We of the trait and the limitations of conventional genetic evaluated a set of 94 DH lines using a series of phenotypic tests that tools. With the advent of new molecular genetic tools, cover seedling resistance and resistance mechanisms: antixenosis, antithe search for genes involved in complex traits has bebiosis, and tolerance. QTL analysis detected six QTLs on chromosomes come a rapidly developing area of research. In the past 1, 2, 6, and 7 associated with resistance to BPH in this mapping populadecade, there has been great progress in identifying tion. The QTLs on chromosome 7 (Est9-RZ337B) and 2 (RG157chromosomal regions that influence quantitative resis-RZ318) showed their association with seedling resistance and antibiotance to insects in many plants (Yencho et al., 2000). sis, respectively. Four QTLs on chromosomes 1 (RG146-RG345), 6 (RG213-Est2; Pgi2-pRD10B), and 7 (RG773-Est2) showed their IR64, an indica variety adapted to irrigated conditions and Published in Crop Sci. 44:2214-2220(2004.

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Orthopteran fauna in rice ecosystem at Coimbatore were surveyed in the Paddy Breeding Station and Wetlands of Tamil Nadu Agricultural University since 1997. Fifty species of Orthoptera (8 long-homed grasshoppers, 28 short-horned grasshoppers, 3 crickets, 1 tree cricket and 10 pygmy grasshoppers) were recorded in the survey. Those collected from the rice fields were found feeding on rice foliage and grains and a few of the Orthopterans viz., Anaxipha longipennis (Serv.), Metioche vittaticollis (Stal), Metioche bicolor (Stal.) (Trigonidiidae) collected mainly from the bunds were observed to be predators of rice insect pests.

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