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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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DR= Damage Rating susceptible check ICPL 87. In all the other genotypes tested positive 't' values were recorded indicating more preference for the flowers of ICPL 87 as compared to test genotype (Table 39).

4.2.6.2.3 Feeding preference under multi- choice conditions In case of short-duration genotypes greater feeding was observed (Table 40) in flowers of ICP 7203-1 (DR=7.40) followed by those of ICPL 87091 (7) and ICPL 871 19 (7.00). Lowest feeding was observed in T 21 (0.80). In case of long-duration genotypes lowest feeding was observed in ICPL 84060 (4.10).

Relative preference by the ld instar H armigem larvae towards 4.2.6.3

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(1.25), followed by ICP 7203-1 (1.40), while highest pod damage was observed in pods of lCPL 87091 (7.40) after 48 h (Table 41). In case of long duration genotypes, there were no significant differences in larval feeding on pods. Highest damage rating was observed in pods of the susceptible check, ICPL 87 (7.50) followed by ICP 7035 (1.SO) (Table 42).

Effect of extracting the pod surface chemicals by different 4.2.6.3.2

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pods extracted in methanol and distilled water. In case of susceptible check, ICPL 87 there were no differences in the feeding in case of control pods, and the pods Table 39: Relative feeding preference by the third instar larva of H.armgera towards flowers of 12 pigeonpea genotypes under dual-choice condition (2001-2002)

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- R Resistant check, S Susceptible check.

* Damage rating (1=10% flowers damaged and 9 = 80% flowers damaged) Table 40: Relative feeding preference by the third instar larva of H armigera towards flowers of 12 pigeonpea genotypes under multi-choice conditions (2001-2002)

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- R Resistant check, S Susceptible check.

Means followed by same letter do not differ significantly.

* Damage rating (1=10% flowers damaged and 9=80% flowers damage) Table 41: Relative feeding preference by the third instar larva to H.armigera towards pods of eight pigeonpea genotypes underhulti-choice condition (2001-2002)

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Mean F Prob.

LSD at 5% CV(%) R - Resistant check, S Susceptible check.

Means followed by same letter do not differ significantly.

Damage rating (1=10% pods damage and 9=80% pods damage) Table 42: Relative feeding preference by the third instar larva to H.armigera towards pods of four pigeonpea genotypes under multi-choice condition (2001-2002)

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Controls ICPL 332 (R) 1CPL-87 (S) Mean F Prob.

LSD at 5% CV% R Resistant check, S - Susceptible Check Means followed by same letter do not differ significantly.

Damage rating (1=10% pods damage and 9=80% pods damage) extracted in distilled water and methanol. In case of ICPL 84060, ICPL 871 19 and ICP 7035 greater feeding was recorded in pods extracted in hexane compared to pods extracted in methanol. The results suggested that the compounds extracted in hexane and methanol were important in determining feeding preference by the H.armigera larvae.

Under dual-choice conditions, the larvae were offered a choice between a control pod and a pod extracted in hexane or methanol or distilled water.

Greater feeding was recorded in pods extracted in hexane as compared to the control pods. When a choice was offered to the larva between a control pod and a pod extracted in hexane negative 't' values wers recorded for ICP 7035, ICPL 87, ICPL 98008, lCPL 87091, ICPL 88039, ICPL 98001, ICPL 84060, and ICP 7203-1 suggesting greater feeding in pods extracted with hexane compared to control pods.

For ICPL 332, ICPL 187-1, and T 21 the pod damage ratings were less on pods extracted with hexane compared to the control pods (Table 43).

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and pod extracted in methanol, negative 't' values were observed in case of ICPL 187-1, ICPL 87, ICPL 98008, ICPL 87091, ICPL 88039, ICPL 98001 and ICPL 871 19 indicating greater damage in pods extracted in methanol than on the control pods. For ICPL 332, ICP 7035, lCPL 84060 and T 21 the damage in control pods was greater when the pods were extracted with methanol (Table 44).

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pods extracted in distilled water, negative 't' values were observed in case of ICPL 87091, T 21 and ICP 7203-1 pods indicating more damage in pods extracted with water compared to the control pods. For the other genotypes, the damage ratings were more in control pods as compared to the pods extracted in distilled water (Table 45)

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Under protected conditions, the differences in pod damage ratlngs among the genotypes were not s~gnificant(Table 46) However under protected condition, the differences were significant among the genotypes tested In case of long- duration genotypes, lowest pod damage ratings was observed in lCPL 332 (3 33) followed by ICPL 84060 (5 00) while in the short duration genotypes lowest pod damage rating was observed In ICPL 98001 (6 OO), followed by ICPL 88039 (8 00) and ICPL 87 (8.33)

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Under protected conditions, there were no significant differences In per cent pod damage (Table 46). However, under unprotected conditions lowest pod damage was recorded in ICPL 332 (22 90%), followed by ICP 7035 (24 40%), ICPL 98001 (57 90%), and ICPL 7203-1 (64 90%). The susceptible checks ICPL87 and ICPL 871 19 suffered a pod damage of 83 2% and 67% respectively

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protected conditions compared to the unprotected conditions (Table 47) Among the long duration genotypes higher 100-seed weight was recorded for ICPL 871 19 (1 1.44 g) under protected conditions and 10.70 g under unprotected conditions. In case of ICPL 871 19 and ICPL 7035 (because of compensation) significantly high seed weight per 100 grains was recorded under unprotected conditions. In case of short-duration genotypes higher 100-seed weight was recorded for ICPL 87091(9.69 g under protected and 9.91 g under unprotected conditions).

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Significantly high grain yield per hectare was recorded under protected conditions as compared to unprotected conditions (Table 48). Highest grain yield per hectare was obtained in ICP 7203-1 (7408 kg) followed by ICPL 187-1 (4495 kg) among short-duration genotypes and ICPL 332 (5551 kg), followed by ICPL 87119 (5257 kg) in case of long-duration genotypes under protected conditions. Under unprotected conditions among long-duration genotypes highest grain yield was obtained in ICPL 332 (4361 kg), followed by ICPL 187-1 (3 188 kg), ICPL 84060 (3 126 kg). In case of short-duration genotypes highest grain yield was obtained in ICPL 187-1 (3 188 kg).

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332 (0.21), and ICPL 84060 (0.24), were the most tolerant genotypes followed by ICPL 87 (0.29). ICPL 87119 (0.51), T 21 (0.64) and ICPL 88039 (0.69). Highest grain yield reduction i.e., avoidable loss was recorded on ICPL 187-1 (36.46 %) followed by T 21 (34.06%), ICPL 98008 (34.80%) and ICPL 88039 (34.23%)

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In the unsprayed field among the long duration genotypes lowest number of eggs were recorded on ICPL 871 19 (4.28) followed by ICPL 84060 (4.52). Among the short duration genotypes, lowest number of eggs were recorded on ICPL 187-1 (4.27). Total number of larvae were more on ICP 7035 (4.46) and less on ICPL 332 (4.21) followed by ICPL 84060 (4.37) among the long duration genotypes. Among the short duration genotypes lowest number of larvae were recorded on ICPL 98001 (4.04) (Table 49). The total number of eggs and larvae were more during unsprayed condition and less under sprayed conditions (Table 50).

In the sprayed field lowest number of eggs were recorded in the ICPL 84060 (0.59) followed by resistant check ICPI. 332 (1.15) among the long duration genotypes. In case of short duration genotypes lowest number of eggs were recorded in ICPL 98008 (0.88). The total number of larvae were less in ICP 7035 (0.23) followed by ICPL 332 (0.14) in case of long duration genotypes. In case of short duration genotypes lowest number of larvae were recorded in ICPL 98008 (0.12) (Table 50).

Correlation between pod borer damage and yield in pigeonpea 4.3.7

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There was a positive and significant correlation between pod damage rating and pod damage per cent (0.85). There was a negative correlation between grain yield and pod damage rating (-0.62). This indicates that as the pod damage rating increases the yield decreases (Table 51). Principal component analysis of number of eggs, larvae, pod damage rating, damage per cent and yield indicated that ICPL 87, lCPL 87091, ICPL 98001, T 21, ICPL 187-1 are resistant genotypes; ICPL 98008, ICPL 871 19 are susceptible genotypes; ICPL 332, ICP 7035, ICPL 88039, ICP 7203-1, ICPL 84060 are moderately resistant genotypes (Fig. 15).

Table 51: Correlations between pod borer damage and yield in 12 pigeonpea genotypes (2001-2002)

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* Significantlydifferent at 5% probability.

FiglS: Principal eompontnt annlyair on number olcggr. larvae. damage rating, damage perantage and yldd Chapter V

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The results obtained in the investigation on Mechanisms of resistance to Helicoverp armigera (Hubner) in pigeonpea [Cajamrs cajan (L.) Millsp.] are dicussed in this chapter.

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ICPL 84060 (52%) and ICPL 88039 (47%). These genotypes were stable in their reaction to H. armigera over seasons ICPL 871 19 was high yielding, but the pod damage was high, with slope l and unit rms value, suggesting that this genotype is more susceptible under climatic conditions favourable to H. armigera. In case of ICPL 7203-1, pod damage was low, and grain yield was high, with a unit slope and rms value of 4. This indicated that genotype ICP 7203-1 is unstable in its reaction to pod borer damage. In case of ICPL 98008, less pod damage and high grain yield were observed with a unit slope and minimum rms values which indicated its stability of reaction to H.armigera damage.

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slope were significantly less than one, and rms = 0; indicating stable reaction to pod borer damage. In case of ICPL 187-1, the slope was greater than one with minimum rms values, suggesting unstable reaction to H,armigero over seasons.

During the 2000 cropping season, pod borer damage was significantly lower in lCPL 187-1 (21.75%), followed by ICPL 84060 (22.68%) and ICPL 98001 (24.32%), which were on par with the resistant check, ICPL 332 (31.09% pod damage). The highest pod damage was recorded in T 21 (52.29%), while the susceptible check ICPL 87 suffered 52.22% pod damage. In case of ICPL 87091, the damage caused by H,armigera to foliage was more compared to the other genotypes tested.

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damage was recorded in ICPL 187-1 (44.8%). which was lower than the damage in the resistant check, ICPL 332 (56.09%). For ICPL 7203-1, ICPL 84060, and ICPL 98008; the pod borer damage was on par with that of the resistant check, ICPL 332.

Highest pod borer damage was recorded in ICPL 98001 (89.25%), which was on par with the susceptible check, ICPL 87 (83.50%).

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ICP 332 (2.61 kg per plot) during the 2000-2001 cropping season. Grain yields of ICPL 187-1, lCPL 87119 and ICPL 84060 were on par with each other.

Significantly low grain yield was recorded in lCPL 87091 (0.031 kg per plot), which was on par with that of the susceptible check, ICPL 87 (0.25 kg per plot). In the second season (2001-2002), the grain yields did not differ significantly but grain yields were numerically greater in ICPL 332 (3.77 kg), ICPL 84060 (3.40 kg), ICPL 871 19 (3.23 kg), ICPL 7203-1 (2.28 kg), and ICPL 187-1 (2.26 kg). In the first planting, highest grain yields were obtained in ICPL 332, ICPL 7203-1, ICPL 84060, ICPL 98008 and T 21, and lowest in ICPL 87091, which was on par with the susceptible check, ICPL 87. During 2001-2002 season significantly higher grain yield was obtained for ICPL 332 (2.56 kg), followed by ICPL 187-1 (1.90 kg), ICPL 84060 (1.78 kg) and lCPL 871 19 (1.59 kg) as compared to ICPL 87.

Amongst the short-duration genotypes; ICPL 187-1, lCPL 98008, ICPL 7203-1, T 21 and ICPL 88039 had low pod borer damage and reasonably high grain yields compared to the other genotypes tested. All these genotypes were determinate types. ICPL 87 and ICPL 98001 had high pod damage and low yields.

ICPL 87091 exhibited the highest pod borer damage and determinate type of growth habit.

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genotypes were of indeterminate growth habit. ICP 7035 was also high yielding, but the pod borer damage in this variety was higher than ICPL 332 and the grain yield was low. ICP 7035 suffered more damage at the flowering stage than at the poding stage. T i had indeterminate type of growth habit.

hs Singh and Choudhary (1980) reported that varieties with bold seed were most suited for growing in favourable environments. Tomer el al. (1973) also concluded that large seeded chickpea cultivars were unstable and were only suitable for high-yielding environments. In the present studies, genotypes with bold grain (ICP 7035 and ICPL 871 19) were unstable in grain yield and were susceptible to H.armigera.

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grain yield. The hybrid MTH 9 performed consistently well under low management conditions with a highly significant regression coefficient (bi =1.96), while ICPL 227 exhibited stability in its performance over the years. The extent of genotype x environment interaction for grain yield and its components in 29 pigeonpea lines were evaluated in 3 environments by Dahiya and Singh (1993). Six genotypes were stable for grain yield as they exhibited high mean performance, a unit regression coefficient, and a very low magnitude of deviation from regression.

Ten genotypes of short-duration pigeonpea were evaluated for stability by Tyagi and Aganval (1995). Highly significant mean squares were observed for genotypes, and genotype x environment interaction. ICPL 151 was the most stable genotype, in which the regression coefficient did not deviate from unity and had a non-significant minimum deviation from regression.

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