Investigations on self-compatibility and extent of self and cross pollination in cashew

To address the issues of presence of self-incompatibility and extent of self and cross pollination in cashew, studies were carried out employing eight cultivars and four types of pollinations viz., self-pollination, geitonogamy, hand self-pollination, hand cross pollination. Observations on percentages of initial fruit set, final fruit set, fruit shed as well as total fruit set were recorded. The cultivars differed significantly for all the traits studied. In hand self-pollination, initial fruit set varied from 7.97 to 17.03 per cent. The final fruit set ranged from 10.47 to 3.13 per cent. The fruit shed varied from 9.53 to 1.85 per cent. The total final fruit set varied from 12.50 per cent (NRCC Sel-2) to 41.88 per cent (Ullal-3). In hand cross pollination, the initial fruit set varied from 9.30 to 18.83 per cent. The final fruit set ranged from 3.77 to 7.90 per cent and the fruit shed varied from 4.12 to 15.06 per cent. The total final fruit set ranged from 15.06 per cent (Priyanka) to 31.58 per cent (NRCC Sel-2). Cultivar, Ullal-3 showed more fruit set in self-pollination and geitonogamy. All the varieties were found to be self- compatible and hence self-incompatibility does not seem to operate in cashew. Six varieties were cross-compatible and two were partially cross-compatible as female parents. The study indicated that self as well as cross pollination play significant roles in fruit set in cashew. The estimates of heritability in broad sense and genetic advance for final fruit set were high in self- pollination and geitonogamy, high and moderate in hand self and cross pollinations

Genetic architecture of cashew germplasm accessions

The variability and genetic architecture was assessed deploying 13 important quantitative characters of 478 cashew germplasmaccessions evaluated and conserved in National Cashew Field Gene Bank, Directorate of Cashew Research, Puttur in India.Considerable variability was observed for all characters and the highest co-efficient of variation (CV) was observed for sex ratiofollowed by cumulative yield per plant and apple weight. The lowest CV was observed for shelling percentage followed by shellthickness. Frequency distribution patterns showed highly positively skewed distribution for characters such as nut weight, sexratio, apple weight and apple to nut ratio. Genetically, it is evident that decreasing alleles are in excess and dominant for thesecharacters. Tree spread, kernel weight and cumulative yield per plant showed moderately positively skewed distribution indicatingdecreasing alleles are in slight excess and dominant. Flowering intensity showed moderately negative skewed distribution indicatingthe presence of increasing alleles in slight excess and their dominant nature. Tree height, shell thickness, flowering duration,shelling percentage and leaf area showed approximately symmetric distribution indicating increasing and decreasing alleles are inequal proportion and the dominance is ambi-directional. Significant positive correlations with cumulative yield per plant wereobserved for tree height, tree spread, sex ratio, flowering duration, apple to nut ratio, shelling percentage and leaf area andsignificant negative correlation for shell thickness. The present germplasm collection represents sufficient number of accessionsfor both quantitative and qualitative characters in desired direction. However, based on the frequency distribution patterns, it isimperative to collect germplasm with dwarfness, less tree spread, high nut weight, apple weight and high yield

Hybrid vigour and variability for key growth characters and yield in cashew (Anacardium occidentale L.)

Hybrid vigour and assessment of genetic variability for important growth characters and yield traits in cashew were studied in eight cashew hybrids.The analysis of variance for the phenotypic data for 12 characters revealed significant variation among the genotypes except for tree spread, flowering laterals per m2, non-flowering laterals per m2 and sex ratio.The highest nut weight was observed in H-125 (12.07 g) whereas the lowest was in H-2452 (5.08 g).The maximum nut yield was noticed in hybrid H-126 with 5.96 kg tree-1 while NRCC Selection-2 recorded lowest with 0.53 kg tree-1. The standard heterosis over two checks, bold nut check (NRCC Sel-2) and high yielding check (Bhaskara) and variability parameters such as genotypic coefficient of variation, phenotypic coefficient of variation, broad-sense heritability and genetic advance were estimated. For nut weight, standard heterosis over bold nut check varied from -34.54 to 55.54 per cent and six out of eight hybrids viz., H-43, H-66, H-68, H-125, H-126 and H-2473 showed significant and positive standard heterosis. Standard heterosis over the high yielding check, varied from -38.93 to 300 per cent and it was significant and positive in two hybrids viz., H-126 and H-125 with 300 per cent and 214.09 per cent, respectively.The hybrid vigour was not significant for trunk girth, tree height, tree spread, number of flowering laterals per m2 and sex ratio. Notably, five hybrids presented more than 20 per cent standard heterosis for nut weight over bold nut check which may serve as a useful source of breeding material. Two hybrids viz., H-125 and H-126 showed good hybrid vigour for nut weight and yield over two checks and thus have been inducted into multi-location trials and also under consideration for release

Seedling selection in open pollinated genotypes of cashew (Anacardium occidentale)

In a highly heterozygous crop like cashew (Anacardium occidentale L.), selection of high yielding trees from a seedling population of existing varieties is one of the ways of development of variety. Hence an experiment was undertaken to study the extent of variability in seedlings of six popular genotypes, viz. NRCC Sel 2, Vengurle 4, Vridhachalam 3, Bhaskara, VTH 174 and VTH 30/4 and to identify promising trees. Eighty open pollinated seeds each from trees belonging to six genotypes were collected; seedlings were raised and planted during 2007 at Directorate of Cashew Research, Experimental Station, Shantigodu. Growth parameters like trunk girth, tree height, tree spread and nut yield per tree were recorded. The progeny performance in different varieties revealed that the mean nut yield per tree was highest with 2.46 kg in Vridhachalam 3. With regard to individual tree performance tree number 480 belonging to VTH 30/4 recorded highest yield of 6.9 kg nuts/tree. The frequency distribution patterns showed that data of trunk girth was moderately negatively skewed implying increasing alleles are in slight excess and dominant for this trait. Whereas tree height and tree spread distributions were moderately positively skewed indicating decreasing alleles are in slight excess and dominant for these traits. The nut yield showed highly positively skewed distribution revealing decreasing alleles are in excess and dominant. The kurtosis was very high for nut yield indicating that yield variability is due to a few extreme differences from the mean. It was observed that trunk girth and tree spread were positively correlated with nut yield. The study could identify one promising seedling (T No.480), a seedling progeny of VTH- 30/4 in terms of nut yield

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Not AvailableCashew has become an important nut crop in India owing to its nutritional value and export earnings. The productivity of cashew in India is low because of several reasons and hence India imports raw nuts from other countries to meet the demand of its processing industries. Several studies have shown that inadequate pollination plays an important role in low productivity of cashew in addition to other factors. Hence, it is imperative to understand and address the issue of pollination in cashew to increase the productivity. In this regard, an attempt has been made here to review the research related to pollination in cashewNot Availabl

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Not AvailableHybrid vigour and assessment of genetic variability for important growth characters and yield traits in cashew were studied in eight cashew hybrids. The analysis of variance for the phenotypic data for 12 characters revealed significant variation among the genotypes except for tree spread, flowering laterals per m2 , non-flowering laterals per m2 and sex ratio. The highest nut weight was observed in H-125 (12.07 g) whereas the lowest was in H-2452 (5.08 g). The maximum nut yield was noticed in hybrid H-126 with 5.96 kg tree-1 while NRCC Selection-2 recorded lowest with 0.53 kg tree-1. The standard heterosis over two checks, bold nut check (NRCC Sel-2) and high yielding check (Bhaskara) and variability parameters such as genotypic coefficient of variation, phenotypic coefficient of variation, broad-sense heritability and genetic advance were estimated. For nut weight, standard heterosis over bold nut check varied from -34.54 to 55.54 per cent and six out of eight hybrids viz., H-43, H-66, H-68, H-125, H-126 and H-2473 showed significant and positive standard heterosis. Standard heterosis over the high yielding check, varied from -38.93 to 300 per cent and it was significant and positive in two hybrids viz., H-126 and H-125 with 300 per cent and 214.09 per cent, respectively. The hybrid vigour was not significant for trunk girth, tree height, tree spread, number of flowering laterals per m2 and sex ratio. Notably, five hybrids presented more than 20 per cent standard heterosis for nut weight over bold nut check which may serve as a useful source of breeding material. Two hybrids viz., H-125 and H-126 showed good hybrid vigour for nut weight and yield over two checks and thus have been inducted into multi-location trials and also under consideration for release.ICAR-Directorate of Cashew Research, Puttur-574 202, Karnataka, Indi

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