The patterns and extent of genetic variation among 56 cashew germplasm with respect to 32 qualitative and 33 quantitative traits were evaluated for two successive years in the present study. Additionally, maturase K gene-based genetic diversity among those breeding materials was also assessed. The cashew hybrids were developed from five crosses (local parent × 2/9 Dicherla; H-2/15 × red hazari; WBDC-V × JGM-1; BLA-39-4 × H-2/15 and H-2/15 × yellow hazari) involving eight parents of Indian cashew. Different genotype groups (parents and their hybrids) showed significant variation in both the years of assessment based on quantitative characters. The highest Shannon–Weaver diversity (H′) was obtained for the colour of the young leaf (0.96), possibly indicating differential exposure to sunlight, mixing of various pigments and another set of chemicals such as phenolics, carotenoids, etc. in trees. From correlation studies, canopy spread, tree spread, nuts/m2 and nuts/panicle were found to be significantly and positively correlated with nut yield. In the year 2021, nuts/m2, area and tree height were the significant explanatory variables that explained 80% of the variation in the yield, whereas in 2022, nuts/m2, tree area, nuts/panicle, kernel weight, shell thickness, inflorescence breadth and sex ratio explained 86% of the variation. Principal component analysis indicated that the genotypes under study are diverse enough to be exploited for the future cashew improvement programmes.

ICAR-Directorate of Cashew Research is the nodal agency for conducting cashew research and manages the largest field gene bank in India. Cashew is a perennial tree and needs more land and other resources to maintain accessions. Conservation through seeds is not feasible because of cross-pollination. Tissue culture efforts to regenerate plants from mature explants are not successful. Therefore, efficient management of the filed gene bank particularly utilization requires designation of the core collection representing the spectrum of diversity present in the entire collection. In this study, a relatively new technique, the advanced M strategy with heuristic approach was deployed to develop the core collection. Sixty-eight morphometric characters of 478 accessions were subjected to analysis resulting in the core collection of 49 accessions. Further, another core collection of same number was constituted by K-Means clustering to compare the efficiency of two approaches. The validation parameters like mean difference, variance difference, coincidence rate, variable rate and class coverage among others were employed for comparative analysis. The results of these parameters revealed that the core collection designated by heuristic approach was better able to efficiently represent and retain the diversity of the entire collection compared with the core identified by clustering approach. Future conservation and breeding efforts will be focused on establishing a separate block in the field gene bank having 49 accessions of cashew core collection.

Introduction. Originaire du Brésil, l'anacardier est largement présent dans la zone intertropicale. Une synthèse sur les intérêts économiques et les différentes voies de valorisations des produits de cet arbre a été effectuée. L'anacardier. De part sa résistance, notamment aux périodes de sécheresse, l'espèce Anacardium occidentale (anacardiacée) est adaptée à de nombreuses zones tropicales. Malgré sa tolérance aux attaques parasitaires, elle peut être sensible à certains insectes et attaques fongiques comme l'oïdium. Les rendements moyens obtenus pour la noix sont d'environ 600 kg × ha-1 × an-1 ; ils sont susceptibles d'être améliorés grâce à la sélection variétale. La noix de cajou. Elle est le fruit de l'anacardier au sens botanique du terme. L'amande est riche en lipides et contient environ 20 % de protéines. En 1999, les principaux producteurs mondiaux de noix de cajou ont été l'Inde, le Nigéria, le Brésil et la Tanzanie, qui ont produit chacun plus de 100 000 t × an-1. Après concassage de la coque et émondage, ce produit à forte valeur ajoutée est le plus souvent exporté. La pomme de cajou. Elle correspond au pédoncule hypertrophié de la noix qui possède à maturité une chair juteuse et sucrée. Ses principales caractéristiques sont son astringence et sa teneur élevée en vitamine C (200-300 mg × 100 g-1). La pomme de cajou est assez peu valorisée sauf en Inde et au Brésil, notamment sous forme de jus de fruit. Autres productions. Le baume de cajou est une production secondaire assez originale : extrait des coques de la noix, ce liquide corrosif, riche en composés phénoliques, est utilisé dans l'industrie chimique. Conclusion. La culture de l'anacardier, avec sa diversité de produits et notamment avec la noix qui est bien intégrée aux marchés internationaux, semble pouvoir constituer une source intéressante de revenus pour les zones tropicales sèches. Néanmoins, la pomme mériterait d'être mieux valorisée car elle reste encore un sous-produit de l'industrie de la noix de cajou.

The virus Rhabdionvirus oryctes Huger was tried against the root and stem borer of the cashew (Anacardium occidentale L.) in Sri Lanka by pouring a virus suspension into the galleries, releasing virus-infected adults and placing virus-mixed sawdust at the base of the infested stem. Results obtained after several surveys showed that the sawdust technique gave more positive results. The establishment and infection of the virus in the beetle population accounted for a reduction in the beetle damage to the tree in certain pockets of the cashew plantation.

Laboratory and field studies were made to investigate the toxicity, mode of action, and persistence of technical DDT and y BHC when applied to the cashew in Sri Lanka to control the mirid bug, Helopehis antonii Sign. The insecticides were tested at concentrations previously used in field trials.

Mirid nymphs were placed on the nuts and the rate of knockdown and mortality after exposure for a test period was recorded. These tests showed that BHC had a higher toxicity and acted more quickly than DDT. BHC had a powerful and transient fumigant action over DDT, which had no fumigant effect at all. Persistence was studied by treating cashew leaves and nuts growing under natural conditions and then testing the residual deposit at intervals.

It was concluded that BHC would be more effective than DDT when treating mature cashews because, in addition to its higher toxicity and quicker action, its fumigant action would compensate for incomplete coverage by low-volume spraying.