Standardisation of vegetative propagation technique in cashew with a view to reduce tho post-separation mortality of alr-layers

Abstract

Investigation on the different aspect of the poet separation mortality of air-layers worn carried out on four year old cashew trees at the main campus at Vellanikkara of the Kerala Agricultural University during tho period of February 1977 to Juno 197Q. Air-layering was done at fortnightly interval and observation on the shoot growth worn recorded to find out whether there is any correlation between rooting of air-layer and tho shoot growth cycles. Wedge grafting was also tried no an alternative method for air-layerlng. The best time for air-layering in cashew was from February to April at which time the tree were in active growth phase as indicated by tho maximum percentage of shoot extension growth. Percentage of rooting in different Months wan positively correlated with tho percentage of shoots in flush and tho rate of shoot extension grown in tho respective month. Rooting was positively correlated with maximum temperature in tho respective month® and negatively correlated with total rainfall. Establishment was better in layers planted in polythene bags with the medians supplied with nutrient solution ns ooapared with pinnto not supplied with nutrient solution but the differences were not significant. Juno find July which arc tho heavy rainfall months in Kerala wore tho boot months for planting out air-layers directly in tho field. Establishment was improved by Keeping the layers in mist chamber. Treatment with IBA ppn and NAH 500 ppm produced the maximum number of rooted air-layers. treatment with IBA 250 ppm was tho boot in respect of the coon length of roots while IBA 500 ppm produced maximum number of roots per layers The highest percentage of establishment of air-layers was recorded by layers treated with IBA 500 ppm. Wedge grafting on eight month old cashew seedlings, though needed further standardisation, gave n better success in March compared to February.