Evaluation of resistance of wild rices,Oryza spp., to the whitebacked planthopper,Sogatella furcifera (Horvath) (Homoptera: Delphacidae)

Evaluation of wild rice species for resistance against major insect pests of rice was carried out in both field and greenhouse conditions. A total of 219 wild rice lines were evaluated under field conditions against yellow stem borer, Scirpophaga incertulas (Walker) and leaf folder, Cnaphalocrocis medinalis (Guenee). Of the selected 185 lines tested by “standard seed box screening technique” against whitebacked planthopper, Sogatella furcifera (Horvath), 20 were found to be resistant, 54 moderately resistant, 88 moderately susceptible, and 23 susceptible. Out of the 185 wild rice lines tested against all the three major pests, 17 lines had multiple resistance. Out of these 17 lines, 14 lines were evaluated for mechanisms of resistance against S. furcifera; they showed antixenosis for feeding, as fewer nymphs settled on them compared to the susceptible O. sativa cultivar TN1. However, the eggs were observed to be randomly distributed on them. Antibiosis was exhibited as the nymphal period was prolonged, while there was a decrease in survival and growth index. Thus, besides possessing multiple resistance against all the three major pests during the present investigation, all these 14 wild rice lines belonging to different Oryza spp. exhibited good antixenotic and antibiotic effects.     

Effects of defoliating insect resistance QTLs and a <Emphasis Type="Italic">cry1Ac</Emphasis> transgene in soybean near-isogenic lines

The crystal proteins coded by transgenes from Bacillus thuringiensis (Bt) have shown considerable value in providing effective insect resistance in a number of crop species, including soybean, Glycine max (L.) Merr. Additional sources of soybean insect resistance would be desirable to manage the development of tolerance/resistance to crystal proteins by defoliating insects and to sustain the deployment of Bt crops. The objective of this study was to evaluate the effects and interactions of three insect resistance quantitative trait loci (QTLs; QTL-M, QTL-H, and QTL-G) originating from Japanese soybean PI 229358 and a cry1Ac gene in a “Benning” genetic background. A set of 16 BC₆F₂-derived near isogenic lines (NILs) was developed using marker-assisted backcrosses and evaluated for resistance to soybean looper [SBL, Pseudoplusia includens (Walker)] and corn earworm [CEW, Helicoverpa zea (Boddie)] in field cage, greenhouse, and detached leaf assays. Both Bt and QTL-M had significantly reduced defoliation by both SBL and CEW and reduced larval weight of CEW. The antibiosis QTL-G had a significant effect on reducing CEW larval weight and also a significant effect on reducing defoliation by SBL and CEW in some assays. The antixenosis QTL-H had no main effect, but it appeared to function through interaction with QTL-M and QTL-G. Adding QTL-H and QTL-G further enhanced the resistance of the Bt and QTL-M combination to CEW in the field cage assay. These results should help guide the development of strategies for effective management of insect pests and for sustainable deployment of Bt genes.     

Inheritance of spontaneous male sterility in pigeonpea

 A male-sterile plant was observed in the UPAS-120 cultivar of pigeonpea (Cajanus cajan). The plant was about 5–7 days late-flowering and had white translucent anthers with complete pollen sterility. The inheritance of this spontaneous male sterility was studied in a cross involving the mutant and fertile UPAS-120, including their F₁, F₂, BC₁F₁ and BC₂F₁ generations. The results suggested that the male sterility was genetic and due to a recessive gene. Received: 12 November 1996/Accepted: 17 January 1997     

Antixenosis phloem‐based resistance to aphids: is it the rule?

1. The concept of plant defence syndrome states that plant species growing in similar biotic or abiotic constraints should have convergent defensive traits. This article is a first step to test the prediction of this concept, by conducting experiments on wild Solanum species (or accessions) that originated from the Andes. The nature and the tissue localisation of the resistance of five wild Solanum species known to be resistant against the aphids Myzus persicae and Macrosiphum euphorbiae were determined by olfactometry and electrical penetration graph experiments. 2. Volatile organic compounds may contribute to wild Solanum resistance, depending on Solanum accessions and aphid species. Volatiles of S. bukasovii and S. stoloniferum PI 275248 were not attractive to M. persicae, whereas S. bukasovii was repulsive to M. euphorbiae. In contrast, volatiles of S. stoloniferum PI 275248 were attractive for M. euphorbiae. 3. Some wild Solanum species presented a generalised resistance in all plant tissues, so as for S. bukasovii and S. stoloniferum PI 275248 against M. persicae. However, except for S. bukasovii which was susceptible to M. euphorbiae, all tested Solanum species presented a phloem‐based antixenosis resistance against the two aphid species. 4. A review of articles focused on the nature of resistance of wild Solanum species against aphids corroborated with our results, i.e. a phloem‐based antixenosis resistance against aphids is the rule concerning the system aphids–wild Solanum species.     

Morphological and chemical components of resistance to pod borer, Helicoverpa armigera in wild relatives of pigeonpea

Host plant resistance is an important component for minimizing the losses due to the pod borer, Helicoverpa armigera, which is the most devastating pest of pigeonpea. An understanding of different morphological and biochemical components of resistance is essential for developing strategies to breed for resistance to insect pests. Therefore, we studied the morphological and biochemical components associated with expression of resistance to H. armigera in wild relatives of pigeonpea to identify accessions with a diverse combination of characteristics associated with resistance to this pest. Among the wild relatives, oviposition non-preference was an important component of resistance in Cajanus scarabaeoides, while heavy egg-laying was recorded on C. cajanifolius (ICPW 28) and Rhynchosia bracteata (ICPW 214). Accessions belonging to R. aurea, C. scarabaeoides, C. sericeus, C. acutifolius, and Flemingia bracteata showed high levels of resistance to H. armigera, while C. cajanifolius was as susceptible as the susceptible check, ICPL 87. Glandular trichomes (type A) on the calyxes and pods were associated with susceptibility to H. armigera, while the non-glandular trichomes (trichome type C and D) were associated with resistance to this insect. Expression of resistance to H. armigera was also associated with low amounts of sugars and high amounts of tannins and polyphenols. Accessions of wild relatives of pigeonpea with non-glandular trichomes (type C and D) or low densities of glandular trichomes (type A), and high amounts of polyphenols and tannins may be used in wide hybridization to develop pigeonpea cultivars with resistance to H. armigera. Handling editor: Robert Glinwood     

Identification and mapping of two brown planthopper resistance genes in rice

The brown planthopper (BPH) is one of the most serious insect pests of rice. In this study, we conducted a molecular marker-based genetic analysis of the BPH resistance of ’B5’, a highly resistant line that derived its resistant genes from the wild rice Oryza officinalis. Insect resistance was evaluated using 250 F₃ families from a cross between ’B5’ and ’Minghui 63’, based on which the resistance of each F₂ plant was inferred. Two bulks were made by mixing, respectively, DNA samples from highly resistant plants and highly susceptible plants selected from the F₂ population. The bulks were surveyed for restriction fragment length polymorphism using probes representing all 12 chromosomes at regular intervals. The survey revealed two genomic regions on chromosome 3 and chromosome 4 respectively that contained genes for BPH resistance. The existence of the two loci were further assessed by QTL (quantitative trait locus) analysis, which resolved these two loci to a 14.3-cM interval on chromosome 3 and a 0.4-cM interval on chromosome 4. Comparison of the chromosomal locations and reactions to BPH biotypes indicated that these two genes are different from at least nine of the ten previously identified BPH resistance genes. Both of the genes had large effects on BPH resistance and the two loci acted essentially independent of each other in determining t he resistance. These two genes may be a useful BPH resistance resource for rice breeding programs. Received: 6 March 2000 / Accepted: 28 July 2000     

云南野生稻抗褐飞虱评价及其抗性基因鉴定

褐飞虱是水稻生产中最严重的害虫之一,从野生稻中发掘抗虫基因,有利于培育具有抗虫能力强的水稻新品种。该研究通过对云南野生稻进行温室和大田抗虫鉴定以及9个已知抗褐飞虱基因的PCR鉴定,发现云南野生稻对褐飞虱表现出不同程度的抗性,尤其疣粒野生稻和药用野生稻对褐飞虱表现出高抗,可作为抗虫基因发掘的优良抗源材料;不同褐飞虱抗性的云南野生稻中含有的抗褐飞虱基因差异很大,3种野生稻中均不含Bph1和Bph18(t)抗病基因,景洪普通野生稻和元江普通野生稻可能含bph2基因,东乡普通野生稻可能含bph2、Bph15和Bph27(t)基因,疣粒野生稻中可能含bph2和bph19(t)基因,药用野生稻和药用野生稻(宽叶型)中可能含bph2和Bph6基因,药用野生稻F1中可能含bph2、Bph14和bph20(t)基因,药用野生稻F2中可能含bph2和Bph27(t)基因或者其同源基因。该研究为快速发掘利用云南野生稻中的抗虫基因奠定了理论基础。     

RFLP mapping of a major bruchid resistance gene in mungbean (Vigna radiata,L. Wilczek)

Summary Bruchids (genus Callosobruchus) are among the most destructive insect pests of mungbeans and other members of the genus, Vigna. Genetic resistance to bruchids was previously identified in a wild mungbean relative, TC1966. To analyze the underlying genetics, accelerate breeding, and provide a basis for map-based cloning of this gene, we have mapped the TC1966 bruchid resistance gene using restriction fragment length polymorphism (RFLP) markers. Fifty-eight F₂ progeny from a cross between TC1966 and a susceptible mungbean cultivar were analyzed with 153 RFLP markers. Resistance mapped to a single locus on linkage group VIII, approximately 3.6 centimorgans from the nearest RFLP marker. Because the genome of mungbean is relatively small (estimated to be between 470 and 560 million base pairs), this RFLP marker may be suitable as a starting point for chromosome walking. Based on RFLP analysis, an individual was also identified in the F₂ population that retained the bruchid resistance gene within a tightly linked double crossover. This individual will be valuable in developing resistant mungbean lines free of linkage drag.     

Pod surface exudates of wild relatives of pigeonpea influence the feeding preference of the pod borer, Helicoverpa armigera

Wild relatives of crops are an important source of resistance genes against insect pests. However, it is important to identify the accessions of wild relatives of crops with different mechanisms of resistance to broaden the basis and increase the levels of resistance to insect pests. Therefore, we studied the feeding behavior of pod borer, Helicoverpa armigera, which is the most damaging pest of pigeonpea, in relation to biochemical characteristics of the pod surface exudates in a diverse array of germplasm accessions belonging to 12 species of pigeonpea wild relatives. Feeding by H. armigera larvae was significantly lower on the unwashed or water-, methanol-, or hexane-washed pods of Canajus sericeus, C. scarabaeoides, Flemingia bracteata, F. stricta, and Rhynchosia aurea than those of C. acutifolius, C. albicans, C. cajanifolius, C. lineatus, D. ferruginea, P. scariosa, R. bracteata, and the cultivated pigeonpea, C. cajan genotypes, ICPL 87, and ICPL 332, although there were a few exceptions. The methanol-washed pods of wild relatives were less preferred for feeding by the H. armigera larvae than the unwashed pods, but the hexane-washed pods were preferred more than the unwashed pods. The results suggested that methanol extracted the phagostimulants from the pod surface, while hexane removed the antifeedants. The high-performance liquid chromatography (HPLC) finger printing of methanol and hexane pod surface extracts showed qualitative and quantitative differences in compounds present on the pod surface of different wild relatives of pigeonpea. Some of the peaks in HPLC profiles were associated with feeding preference of the third-instar larvae of H. armigera. There was considerable diversity in wild relatives of pigeonpea as revealed by principal component analysis based on HPLC fingerprints of pod surface extracts in methanol and hexane, and H. armigera feeding on the pods. Wild pigeonpea accessions with low amounts of phagostimulants and high amounts of antifeedants may be used for introgression of resistance genes into the cultivated pigeonpea to develop varieties with broad-based resistance to H. armigera. There is considerable diversity among the wild relatives of pigeonpea, and the accessions with resistance to pod borer. These can be used to broaden the basis and increase the levels of resistance to H. armigera.     

Genetic control of different types of the aphid resistance in cereal crops

Inheritance of the two main types of the plant resistance to insects was investigated in the sorghum-greenbug (Schizaphis graminum Rond.) and wheat-bird cherry-oat aphid (Rhopalosiphon padi L.) interaction systems. The data obtained support the hypothesis that antixenosis (avoiding of the plant by the insect, given a choice) and antibiosis (adverse effect of the plant on the insect feeding on it) are pleiotropic manifestations of the same genes. This is confirmed by the following facts. (1) Identical patterns of segregation for antixenosis and antibiosis in different cases of sorghum resistance to the greenbug: monogenic control (gene Sgr4), digenic control (Sgr1, Sgr2 and Sgr7, Sgr8), and complementary action of the genes (Sgr9 and Sgr10). (2) Correlated changes in the levels of antibiosis and antixenosis during long-term reproduction of a greenbug clone on the resistant sorghum variety k-1206 (resistance controlled by one gene). (3) Simultaneous expression of antixenosis and antibiosis in F₃ wheat hybrid families to the bird cherry-oat aphid.     

Molecular mapping of a novel gene, Grh5, conferring resistance to green rice leafhopper (Nephotettix cincticeps Uhler) in rice, Oryza sativa L.

The green rice leafhopper (GRH), Nephotettix cincticeps Uhler, is one of the most serious insect pests affecting cultivated rice (Oryza sativa L.) in temperate regions of East Asia. An accession of the wild rice species, Oryza rufipogon Griff. (W1962), was found to be highly resistant to GRH by an antibiosis test. To understand the genetic basis of the GRH resistance, a BC₁F₁ population derived from a cross between a susceptible Japonica variety, Taichung 65 (T65), and a highly resistant accession W1962 was analyzed by quantitative trait loci (QTL) mapping. A single major QTL for GRH resistance was detected on rice chromosome 8. A nearly isogenic population containing segments of the targeted QTL region derived from W1962 was then developed through advanced backcrossing with marker-assisted selection. Further molecular mapping using a BC₄F₂ population revealed that a new resistance gene, designated as Green rice leafhopper resistance 5 (Grh5), was located on the distal region of the long arm of chromosome 8 and tightly linked to the simple sequence repeat markers RM3754 and RM3761. A nearly isogenic line (NIL) carrying Grh5 was subsequently developed in the progeny of the mapping population. The resistance level of Grh5-NIL was compared with those of developed NILs for GRH resistance and was found to have the highest resistance. The DNA markers found to be closely linked to Grh5 would be useful for marker-assisted selection for the improvement of resistance to GRH in rice.     

Genotypic variability and mode of action of Colorado potato beetle (Coleoptera: Chrysomelidae) resistance in seven Solanum species

Accessions from seven wild Solanum species were evaluated in the field for resistance to the Colorado potato beetle, Leptinotarsa decemlineata (Say). The multivariate insect population density data were analyzed using factor analysis. The factors extracted corresponded to relevant phases of the insect's life cycle and provided information on the mode of resistance (antixenosis and antibiosis) of the plant species. S. berthaultii, S. capsicibaccatum, S. jamesii, S. pinnatisectum, and S. trifidum demonstrated both antixenosis and antibiosis but expressed different levels of resistance. The mode of resistance of S. polyadenium seemed to be antibiosis and that of S. tarijense antixenosis. Genetic variability and heritability of insect resistance traits within accessions was trivial or inconsistent for all Solanum species studied.     

Molecular analysis of Arachis interspecific hybrids

Incorporation of genetic resistance against several biotic stresses that plague cultivated peanut, Arachis hypogaea (2n=4x=40), is an ideal option to develop disease resistant and ecologically safe peanut varieties. The primary gene pool of peanut contains many diploid wild species (2n=2x=20) of Arachis, which have high levels of disease and insect resistances. However, transfer of resistant genes from these species into A. hypogaea is difficult due to ploidy level differences and genomic incompatibilities. This study was conducted to monitor alien germplasm transmission, using Random Amplified Polymorphic DNA (RAPD) markers, from two diploid wild species, A. cardenasii and A. batizocoi, into A. hypogaea. Triploid interspecific hybrids were produced by crossing two A. hypogaea cultivars (NC 6 and Argentine) with the two species and by colchicine-treating vegetative meristems, fertility was restored at the hexaploid (C_o) level in the four hybrids. Hexaploids were allowed to self-pollinate for four generations, each referred to as a cycle (C₁, C₂, C_3, and C₄). At each cycle, a backcross was made with the respective A. hypogaea cultivar as the maternal parent and only lineages tracing back to a single hexaploid hybrid were used for RAPD analysis. Analysis of mapped, species-specific RAPD markers in BC₁F₁ to BC₁F₃ hybrids indicated that alien germplasm retention decreased every generation of inbreeding, especially in Argentine and in A. batizocoi crosses. A similar trend was also observed for every cycle in BC₁F₂ and BC₁F₃ families, possibly, due to the loss of alien chromosomes following selfing of hexaploids. RAPD marker analysis of 40–chromosome interspecific hybrid derivatives from the four crosses supported previous reports that reciprocal recombination and/or translocations are the predominant mechanisms for exchange of chromosomal segments. No evidence was found for preferential transfer of alien chromosomal regions to specific linkage groups. The implications for developing disease resistant peanut breeding lines are discussed in light of these findings.     

Dominant and additive resistance to the root-knot nematodes Meloidogyne chitwoodi and M. fallax in Central American Solanum species

 The inheritance of resistance to Meloidogyne chitwoodi and M. fallax in Solanum fendleri, S. hougasii and S. stoloniferum was studied assuming disomic behaviour of these polyploid Solanum species. Various populations were produced from crosses within the wild Solanum species; resistant×susceptible and reciprocal crosses (F₁), self-pollinations (S₁), testcrosses (TC) and self-pollinations (F₂) of resistant hybrids, if possible. For the test crosses with S. hougasii, susceptible genotypes of S. iopetalum were used. In seedling tests, numbers of egg masses were counted after inoculation with M. chitwoodi or M. fallax. Almost all seedlings of the F₁ and S₁ populations of S. fendleri appeared to be resistant, whereas the TC and F₂ populations of three different resistant hybrid genotypes segregated into resistant (having 1 or no egg mass) and susceptible plants (having more than 1 egg mass) at ratios of 1:1 and 3:1, respectively. The results clearly indicate the action of a single dominantly inherited gene, and the symbol R _Mc2 is proposed for this gene. In the case of S. hougasii, F₁ and S₁ seedlings appeared to be mostly resistant. Difficulties were met in producing TC and F₂ populations, and only four TC populations were obtained, which segregated at a 1:1 ratio. These results also indicate the presence of a simple dominant factor. For both S. fendleri and S. hougasii no differences were observed between M. chitwoodi and M. fallax, indicating that resistance genes are the same for both nematode species. The F₁, S₁ and TC populations of S. stoloniferum segregated for the square root number of egg masses into normal-like distributions, which deviated between the Meloidogyne species used. The patterns indicate the presence of several additive genes and one or more genes effective to M. fallax but not to M. chitwoodi. The relationship of resistance genes present in various Central American Solanum species is discussed. Received: 24 September 1996/Accepted: 8 November 1996     

An investigation of the resistance to cabbage aphid in brassica species

Fifteen Brassica species and subspecies, as well as accessions of Arabidopsis thaliana and Eruca sativa, were evaluated for their resistance to the cabbage aphid, Brevicoryne brassicae, in the field and laboratory at Horticulture Research International (HRI) Wellesbourne in 1992. In the laboratory, aphid performance was measured in terms of pre-reproductive period, reproductive period, population increase and insect survival. Using these parameters it was possible to identify brassicas possessing antibiosis resistance. In the field B. brassicae attack was assessed in terms of numbers of insects and it was possible to determine aphid preferences for alighting on different species. High levels of antixenosis and antibiosis resistance were discovered in accessions of Brassica fruticulosa and B. spinescens, in a Brassica juncea breeding line and in Eruca sativa. Partial resistance was found in several other Brassica species. The potential of these various sources as donors of resistance genes to be bred into cultivated brassicas is discussed.     

Molecular mapping of resistance gene to English grain aphid (<Emphasis Type="Italic">Sitobion avenae</Emphasis> F.) in <Emphasis Type="Italic">Triticum durum</Emphasis> wheat line C273

The English grain aphid, Sitobion avenae (Fabricius), is one of the most important insect pests causing substantial yield losses in wheat production in China and other grain-growing areas in the world. The efficient utilization of wheat genes for resistance to English grain aphid (EGA) provides an efficient, economic and environmentally sound approach to reduce the yield losses. In the present study, the wheat line C273 (Triticum durum AABB, 2n = 4x = 28), is resistant to EGA in greenhouse and field tests. To identify the resistance gene, designated RA-1 temporarily, C273 was crossed with susceptible genotype Poland 305 (T. polonicum, AABB, 2n = 4x = 28). The F₁, F₂ and F_2:3 lines were tested with EGA in the field and greenhouse. The results indicated that RA-1 is a single dominant gene, closely linked to the microsatellite markers (SSR) Xwmc179, Xwmc553 and Xwmc201 on chromosome 6AL at genetic distances of 3.47, 4.73 and 7.57 cM, respectively. The three SSR markers will be valuable in marker-assisted selection for resistance to EGA as well as for cloning this gene in the future.     

Identification of quantitative trait loci associated with acylsugar accumulation using intraspecific populations of the wild tomato, Lycopersicon pennellii

 Lycopersicon pennellii LA716, a wild relative of tomato, is resistant to a number of insect pests due to the accumulation of acylsugars exuded from type IV trichomes. These acylsugars are a class of compounds including both acylglucoses and acylsucroses. Intraspecific populations between L. pennellii LA716 and L. pennellii LA1912, the latter an accession that assorts for low-level acylsugar accumulation, were created to study the inheritance of type IV trichome density, acylsugar accumulation levels, percentage of acylsugars that are acylglucoses, and leaf area. The F₂ population was subsequently used to determine genomic regions associated with these traits. The relative proportion of acylglucoses and acylsucroses was found to be largely controlled by a single locus near TG549 on chromosome 3. One locus on chromosome 10 showed significant associations with acylsugar levels. In addition, 1 locus on chromosome 4 showed significant associations with leaf area. Ten additional loci showed modest associations with one or more of the traits examined, 5 of which have been previously reported. Received: 13 March 1997 / Accepted: 19 September 1997     

Performance of an aphid Myzus persicae and its parasitoid Diaeretiella rapae on wild and cultivated Brassicaceae

To determine to what extent wild species related to crops might serve as refuges for insect pests and their natural enemies, we compared the performance of the aphid Myzus persicae and its endoparasitoid Diaeretiella rapae on one cultivar of Brassica napus and Brassica oleracea, two wild species Brassica nigra and Sinapis arvensis, and one cultivar of Solanum lycopersicum. These species differ in traits associated with plant defences that may have an impact on the herbivore and its parasitoid. In contrast to our initial hypothesis, aphid population growth rate was significantly smaller on B. napus than on the other Brassicaceae species. Similarly, the performance of the parasitoid was affected by the host plant on which the aphid was feeding. However, aphid and parasitoid performance was not correlated. Thus, in temporally changing landscapes, pests and natural enemies may utilize crops and wild-related host species with contrasting impacts on their fitness.     

Identification of peanut (Arachis hypogaea L.) RAPD markers diagnostic of root-knot nematode (Meloidogyne arenaria (Neal) Chitwood) resistance

DNA markers linked to a root-knot nematode resistance gene derived from wild peanut species have been identified. The wild diploid peanut accessions K9484 (Arachis batizocoi Krapov. & W. C. Gregory), GKP10017, (A. cardenasii Krapov & W. C. Gregory), and GKP10602 (A. diogoi Hoehne) possess genes for ressitance to Meloidogyne arenaria. These three accessions and A. hypogaea cv. Florunner were crossed to generate the hybrid resistant breeding line TxAg-7. This line was used as donor parent to develop a BC₄F₂ population segregating for resistance. Three RAPD markers associated with nematode resistance were identified in this population by bulked segregant analysis. Linkage was confirmed by screening 21 segregatingh BC₄F₂ and 63 BC₅F₂ single plants. Recombination between marker RKN410 and resistance, and between marker RKN440 and resistance, was estimated to be 5.4±1.9% and 5.8±2.1%, respectively, on a per-generation basis. These two markers identified a resistance gene derived from either A. cardenasii or A. diogoi, and were closely linked to each other. Recombination between a third marker, RKN229, inherited from A. cardenasii or A. diogoi, and resistance was 9.0±3.2% per generation. Markers RKN410 and RKN229 appeared to be linked genetically and flank the same resistance gene. All markers were confirmed by hybridization of cloned or gel-purified marker DNA to blots of PCR-amplified DNA. Pooled data on the segregation of BC₅F₂ plants was consistent with the presence of one resistance gene in the advanced breeding lines. Different distributions of resistance in the BC₅F₂ progeny and TxAG-7 suggest the presence of additional resistance genes in TxAG-7.     

Mechanisms of resistance to Helicoverpa armigera and introgression of resistance genes into F1 hybrids in chickpea

The noctuid pod borer, Helicoverpa armigera is a major pest of chickpea, and host plant resistance is an important component for managing this pest. We evaluated a set of diverse chickpea genotypes with different levels of resistance to H. armigera, and their F₁ hybrids for oviposition non-preference, antibiosis, and tolerance components of resistance under uniform insect infestation under greenhouse/laboratory conditions. The genotypes ICC 12476, ICC 12477, ICC 12478, ICC 12479, and ICC 506EB were non-preferred for oviposition under no-choice, dual-choice, and multi-choice conditions, and also suffered lower leaf damage in no-choice tests as compared to the susceptible check, ICCC 37. Antibiosis expressed in terms of low larval weights was observed in insects reared on ICC 12476, ICC 12478, and ICC 506EB. Weight gain by the third-instars was also low on ICC 12476, ICC 12477, ICC 12478, ICC 12479, and ICC 506EB at the podding stage. Non-preference for oviposition and antibiosis (poor larval growth) were also expressed in hybrids based on ICC 12477, ICC 12476, ICC 12478, ICC 12479, and ICC 506EB as compared to the hybrids based on the susceptible check, ICCC 37, indicating that oviposition non-preference and antibiosis in the F₁ hybrids is influenced by the parent genotype. Loss in grain yield was lower in ICC 12477, ICC 12478, ICC 12479, and ICC 506EB compared to that on ICCC 37. The genotypes ICC 12477, ICC 12478, ICC 12479, and ICC 506EB showing antixenosis, antibiosis, and tolerance mechanism of resistance to H. armigera can be used for developing chickpea cultivars for resistance to this pest.