SCIENTISTS AT the Agricultural Research Station (ARS), Aruppukottai in Virudhunagar district of Tamil Nadu have developed a high yielding custard apple (Annona squamosa) with sweet and large fruits. The Tamil Nadu Agricultural University (TNAU), Coimbatore, released this improved variety recently for commercial cultivation by the farmers.
Christened `APK (Ca) 1', the new high yielding custard apple is a clonal selection from a type collected from the State Horticulural Farm, Courtallam. This variety yielded high in rain-fed black soils recording a mean yield (mean of ten years from 1992 to 2001) of 14.9 kg fruits per tree as against 11.4 kg by `Balanagar' variety. It meant a yield increase of about 30.7 per cent over `Balanagar'.
`APK (Ca) 1' produced about 72 fruits, each weighing on an average 207.5 g, per tree in a year. The total yield recorded per hectare was 7300 kg. The fruits are uniformly medium in size, and are distinctly heart shaped. On maturation, the fruits developed a pale yellow colouration around the tubercles. The fruits are sweet with a TSS (total soluble solids) of 25.5 Brix and an acidity of 2 per cent.
The new variety is very hardy and tolerant to drought and salinity. It grows well even on shallow red and black soils. The ideal planting time is June to September. A spacing of 3 m by 3 m will be adequate for the rain-fed crop, while a wider spacing of 4.5 m by 4.5 m is recommended for irrigated conditions. On an average about 490 plants will be needed to cover a hectare.
The grafts should be planted in pits of 90 cm by 90 cm 90 cm. Initially, the young rootstock may be planted in the pits and in situ budding with the improved variety may be done after three months of planting.
The variety responds well to liberal application of organic nutrients. A nutrient dose of 250 g each of nitrogen and potash and 125 g of phosphorus is prescribed to get good results from this variety.
The nutrients should be applied in two equal splits in May-June and October-November. The sprouts from the rootstocks should be removed periodically until the shoots from the graft are well established.
The field should be kept free of weeds, and the sporadic incidence of mealy bugs should be mechanically removed. This variety is not seriously affected by disease. However, occasional incidence of leaf spot and fruit rot has been observed in the field conditions.
The flower buds in the first two years of planting should be nipped off to encourage good flowering and fruiting in the subsequent years. Fruit bearing commences in grafted or budded plants in 36 to 42 months, and the economic bearing is got from the fifth year.
The optimum productive life span of the variety is 25 years, according to the scientists.
Ideally suited for growing both in the dry and irrigated conditions in the plains of Tamil Nadu, this variety will surely win the admiration of the growers as also the consumers.
It tolerates moisture stress conditions very well and is also found quite suitable for the marginal soils, both black and red, in the semi-arid regions