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«D. ANITHA KUMARI THESIS SUBMITTED TO THE ACHARYA N.G RANGA AGRICULTURAL UNIVERSITY COLLEGE OF AGRICULTURE, RAJENDRANAGAR IN PARTIAI FULFILLMENT OF ...»

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viz., gram, red gram, cotton, tomato, chilli, sorghum and maize on the growth and development of H. armigera On the basis of larval period, pupal period, pupal weight, % pupae formed, % moths emerged and number of eggs laid, gram was found to be the most favourable food, and sorghum the least.

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suitability for H,armigera. Hmimina (1988) found that larval growth was faster on cotton flowers, buds than on cotton leaves, potato leaves, tomato fruit, maize cobs or synthetic diet and no larvae survived on tomato leaves. Young larvae feed on sorghum flowers but older larvae prefer developing grains (Roome, 1975).

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chickpea, the eggs are usually deposited on foliage (Rangarao and Shanower, 1999).

The young larvae of H. armigera usually eat some or all of its egg shell before feeding on the plant. It wanders about nibbling various parts of the plant until it finds a flower bud or flower. Temperature and the host plant affects the development of the larva considerably.

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five or six instars under laboratory conditions at a constant temperature of 26+10°C The head capsule width data supported Dyars hypothesis indicating that the five or six iarval instars observed in H.armigera are fairly constant (Bilapate el a/., 1988).

The larval duration varied from 8 to 12 days in the Punjab, India (Singh and Singh, 1975). The fully grown larva leaves the plant, sometimes by dropping to the ground, and burrows into the soil to a depth of 2.5 to 17.5 cm where it pupates (Pearson and Darling, 1958).

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H. armigera has been carried out at ICRISAT from the mid-1970s to the early 1990s (Lateef and Pimbert, 1990). Genotypes showing consistent differences in extent of pod damage have been identified. In general, genotypes with a determinate growth habit show greater susceptibility to pod damage by H. armigera than indeterminate types (Kushwaha and Malik, 1987; Reed and Lateef, 1990). One reason for this may be that the cluster of flower pods at the end of the branch in determinate types simply makes it easier for larvae to move from one pod to another. Within shortduration determinate types, genotypes ICPL 289 and H 81-95 have shown less susceptibility to pod borer (Kushwaha and Malik, 1987). Among short-duration indeterminate types, ICPL 88039 has proven to be less susceptible under farmers' field conditions (Dahiya er al., 2002). Among medium-duration types, most of which have indeterminate growth habit, ICP 909-EB, PPE 45-2, ICP 1811-E3, ICP 1903-El (ICPL 332), and ICP 10466-E3 have shown less susceptibility (Lateef and Pimbert, 1990), been released primarily on the basis of its resistance to H. armigera.

However, this variety did not prove to be very popular because of its small pod and seed size.

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of pigeonpea varieties resistant to H. armigera appears to be complex problem.

Some pigeonpea varieties with reasonable tolerance to the pod borer are JA 4, GT 100 and Co 6. The bulk of progenies of Pusa 971 based on less than 25% as prime defence can be usefbl in integrated pest management strategy (Dua er al.,2002).

Varieties with high degree of resistance to pod borer need to be developed for commercial cultivation.

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used as a donor parent for incorporating resistance. Although, number of sources of resistance (less susceptibility) to H. armigera have been reported, stability of resistance across locations andlor seasons is not known. Information on genotype x

E) interaction for H.armigera resistance is limited. Therefore, the environment (G x present studies were planned to collect the information about stability of resistance H,armigera in pigeonpea in known sources of resistance available in breeding to program and genetic resource collection at ICRISAT.

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genotypic stability from genotype x environmental interactions. Finlay and Wilkinson (1963) utilized a regression technique proposed by Yates and Cochran (1938) to measure "stability indexes" of barley varieties. They considered linear regression as a measure of stability (i.e., a genotype is more stable with a slope of more than one). Eberhart and Russell (1966) defined a stable genotype is one having a slope equal to one and a deviation from regression equal to zero. This approach has been extensively used by plant breeders (Reich and Atkins 1970; Kofoid el al., 1978; and Virk ef aL, 1985). Breese (1969), Samuel et al., (1978), and Pethani and Kapoor (1985) emphasized that the linear regression should be regarded as a measure of the response of a particular genotype, whereas the deviation around the regression line should be considered as a measure of stability, genotypes with the lowest deviations being the most stable and vice versa.

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regression, a second stability parameter, appears very important, as the genotype x environment (linear) sum of squares was not a very large portion of the genotype x environment interaction.

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yield well in its area of initial selection, but ideally it also must maintain a high yield level in many environments within its intended area of production.





Singh et al. (1988) studied phenological traits in chickpea and analyzed them for stability following Eberhart and Russell (1 966) and indicated the importance of phenological traits for production stability in chickpea.

Dahiya and Singh (1993) studied genotype x environment interaction for yield and its components in 29 pigeonpea lines in 3 environments following Eberhart and Russell (1966). Six genotypes were stable for yield as they exhibited high mean performance, a unit regression coefficient and low magnitude of deviation from regression.

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to Calocoris angustatis (Hemiptera: Miridae) and concluded that the environmental conditions play an important role in determining the interaction between the insects and the host plant.

Singh and Singh (1995) reported positive and significant correlation between the mean of the genotypes and responsiveness to different environments for number of pods per plant, 100-grain weight and single plant yield in chickpea and indicated that the genotypes with high mean were in general, better responsive to favourable environments. There was lack of general association between stability of yield and its components, which calls for cautious selection of genotypes based on yield alone.

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studied stability of yield and its components in chickpea and selected genotypes with high mean, unit regression slope and a non-significant deviation from regression as the measure for selecting promising genotypes for stability of yield. But in case of pod borer resistance, genotypes with lowest damage, ORS (Overall resistance score) and PDS (Pod damage score), unit regression slope and non-significant deviation from regression were stable and resistant to H. armigera.

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interacting variables, including age, feeding status, mated status and egg load (Fitt, 1986, Courtney and Kibota, 1990). Females with higher egg load may be less discriminating and more accepting of low ranking host plants (Minkenberg el al., 1992; Prokopy e l al., 1994).

Mustapha el al., (1998) examined the effect of age specific fecundity, mated status and egg load on host plant selection by H.armigera under laboratory conditions. The physiological state of a female moth (number of mature eggs produced) greatly influences her host plant specificity and propensity to oviposition motivation. Female moths were less discriminating against cowpea a low-ranked host relative to maize (a high ranked host) by the egg load increased. Increased egg load led to greater propensity to oviposit on both cowpea and maize. Distribution of the eggs by the mated females peaked shortly after mating, wd declined steadily

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dusk, initially alternating with feeding, and later becoming the predominant activity until soon after midnight (Pearson and Darling, 1958). Moths are highly selective in their choice of host plant, and / or suitable conditions of development (Hardwick, 1965) According to Roome (1975) H,armrgera oviposit freely in captivity even on unsuitable substrates The preference of this insect to a particular genotype, shown by laying more eggs, indicates the presence of physiological cues which trigger oviposition. These cues may be visual as well as chemical (Schoonhoven, 1990).

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and sparingly on the leaves mostly during the vegetative phase of the host On chickpea the eggs are laid on the leaves, mostly on the underside, and on the plant tissues when the plants are very small In contrast to other hosts, oviposition on chickpea declines with the onset of flowering (King, 1994).

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G. arboreum. Oviposition in general was low on arboreum cottons as compared to hirsutum. Of the number of factors found to affect oviposition, the trichome length on the upper surface of leaf, rather than the density, was positively correlated Oviposition was maximum during April, and was higher on leaves rather than on other plant parts.

Sison e! a]., (1993) conducted oviposition preference experiments under choice and no-choice conditions with 6 pigeonpea genotypes Among these,

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larvae of H.armtgera on ICPL 270, ICPL 332, ICPL 84060,and LRG 30 They observed that egg laying and larval incidence was significantly higher in ICPL 270 compared with LRG 30, lCPL 332 and ICPL 84060 The larval population was significantly more on top leaves, flowers and pods compared wth the middle and bottom parts Among the vegetative and reproductive parts, egg lay~ngwas quite high on floral parts and new pods as compared to foliage

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1903,ICPL 84060,ICPL 87088,ICPL 87089 and ICP 1691)tested for H,armtgera resistance at ICRISAT In 1991,egg and larval counts were lower on borer reststant lines compared to the borer susceptible cultivar, ICP 1691 Ovipositional nonpreference was also confirmed under laboratory conditions (ICRISAT, 1991)

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A.albrcans were as much preferred for oviposition as the cultivated pigeonpeas Among the pigeonpea cultivars, there were only 1 eggs per 1 inflorescences on

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compared to 23 eggs on ICPL 87 (Sharma et al., 2001).

Lakshmipathi (2000) conducted studies on ovipositional preference by H armigera flower colour in pigeonpea. It was found that the number of eggs laid were significantly higher on the yellow flowers compared to red.

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insects by Painter (1951). The effects of antibiosis may be reduction in size, weight, fecundity, abnormal length of life, and increased mortality of insects (Owens, 1975).

Dodia and Patel (1994) studied the biology of the H.armigera on two resistant (ICPL 270 and ICPL 84060) and one susceptible (BDN 2) pigeonpea varieties under controlled temperatures. The observations showed that the larval and pupal mass of larvae fed on developing pods of resistant varieties were significant!^ lower and the duration of both the stages were longer than the larvae fed on the susceptible variety.

The larval mortality remained high, and larval pupation, adult emergence, fecundity and growth index were adversely affected.

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duration Kabuli (large seeded) chickpea genotypes were screened in the laboratory for antibiosis to H. armigera by Sison et al., (1996). Larvae reared on either chickpea leaves or on pods containing green seeds showed significant variation among the desi genotypes for pupal weight and larval survival. Pupae resulting from larvae reared on either pods or leaves of ICCV 7 weighed substantially less than the larvae reared on Annegiri and ICC 3137. Pupae of larvae reared on leaves of ICC 506 weighed substantially less than those reared on ICC 3 137. There was no variation in the measured parameters for the larvae reared on the kabuli chickpea genotypes.

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pod borer in response to choices between the cultivated and wild species of Cajanus was studied by Green et al. (2002). First and second instars fed on a cultivated variety of C. cajan in preference to C. scarbaeoides, and on flowers of C, cajan rather on pods or leaves of C. cajan. Young larvae (first- and second-instars) congregate inside flowers of cultivated variety as they are vulnerable to desiccation and predation. Later instars (third to fifth) prefer to feed on pods due to changes in the nutritional requirements across the instars. Older larvae of lepidoptera have increased appetitive behaviour (Raubenheimer and Barton, 2000) and need more protein (Simpson el al., 1988).

Helicoverpa armigera larvae fed on artificial diets containing powder from ground seeds of resistant and susceptible pigeonpea genotypes indicated that seed coat from brown coloured seeds had an antibiotic effect on the larvae. Most larvae that were fed on the diets containing seed coats died, although a few survived for over 70 days. The white seeded genotypes showed least antibiosis, confirming field observations that most of these genotypes were susceptible to H. armigera (ICRISAT, 1985).

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scarabaeoides, sericea and cajan (ICP I). It was found that the larvae grew more slowly on Aqlosia spp. took longer to pupate, formed smaller pupae, and these adults laid few eggs. The pod walls of A. scarabaeoides are relatively tough, and under field conditions, the pod borer damage is often limited to scarification of the pod surface such that seeds are left intact. Developing pods of C, scarabaeoides are devoid of glandular hairs and have lignified cells just below the epidermis, suggesting that this species also has a mechanical type of resistance in addition to antibiosis.

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