SCI-TECH & AGRI

High-yielding cashew nut hybrid

By Our Agriculture Correspondent

The golden yellow apples of the hybrid cashew produces bold nuts of export quality

The golden yellow apples of the hybrid cashew produces bold nuts of export quality  

SCIENTISTS AT the Cashew Research Station of the Kerala Agricultural University at Madakkathara near Thrissur have developed a hybrid cashew variety with bold nuts and high quality. This hybrid has been released for commercial cultivation by the Kerala Agricultural University as 'Raghav', according to Dr. P. S. John, Associate Professor and Head of the research station.

The initial breeding work was done under the supervision of scientists Dr. V.K. Damodaran and Dr. Veeraraghavan. The field evaluation data of the variety from 1973 were compiled and its release as a new variety was proposed by Dr. P.S. John, Associate Professor and Head and Dr. V. G. Jayalekshmy, Assistant Professor (Plant Breeding and Genetics) at the research station. It is named as `Raghav' after the scientist, Dr. Veeraraghavan, who contributed significantly to its development.

The cashew hybrid `Raghav' is derived by crossing cashew cultivars ALGD-1-1 and K-30-1. The trees of this hybrid are of medium size, and they grow to a height of about 8.5 m. The flowering season commences in the middle of January, and the flowering duration is 70 days. The hybrid has high yield characters (best yield reported is 14.65 kg nuts per tree per year), with a bold nut size of 9.2 g and good export grade of W 210. The kernel weight is 2.27 g and the shelling percentage is 26.6. The apple is golden yellow with 58.92 per cent juice. The hybrid is propagated through vegetative means. Soft wood grafting is the best method of multiplication. The scion should be selected from the specific variety for graft production. It is well suited to laterite and red loamy soils. It has been found to do well in all the regions of Kerala excepting the high altitudes. The hybrid was included in the multi location trials (MLT) planted during 1986 under the All India Coordinated Research Project (AICRP) on Cashew and was found suited to all cashew growing States of the country.

The grafts can be planted in moderately fertile soils. They should be planted in pits of 50 cm by 50 cm by 50 cm at an espacement of 7.5 m x 7.5 m. The pits are to be filled with topsoil and 5-10 kg well ripened farmyard manure. Liberal quantities of organic manure such as vermicompost and coirpith compost can be applied. The grafts should be planted after carefully removing he polythene tape covering the joint of the scion and rootstock. The graft union should be kept at least 2.5 cm above the ground level.

Staking should be done immediately after planting to avoid any damage to the young plants. The pits should be mulched, and the young plants should be provided with adequate shade during the scorching summer.

Regular weeding should be taken up during August-September, and the plants should be periodically inspected for stem and root borer attack.

This is particularly necessary in replanted cashew plantations. Organic manure can be liberally added to meet the nutrient demand of the growing plants. The best seasons for manuring are June-July and August-September.

The incidence of die-back disease and tea mosquito bug should be addressed by using eco-friendly fungicides and botanical insecticides.

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