PhD 1998

Five experiments were conducted at Cashew Research Station, Kerala
Agricultural University, Madakkathara during 1996-98 to identify drought tolerant
varieties of cashew, to study the response of cashew to applied N at different levels
of drip irrigation and to assess the tolerance of cashew varieties to N, P and K
deficiency in soil. The abstract of the experiments is given below.
Exp. I. Varietal variation in drought tolerance
The varieties H-1591, M-26/2, V-5 and M-44/3 are drought tolerant and
K-22-1 is drought sensitive.
Exp. II. Response of cashew to applied N at different levels of irrigation (drip)
N application @ 1500 g per tree per year along with irrigation @ 80 litres
per tree per day (through drip) is essential in the state of Kerala for obtaining best
results from cashew.
Exp . lIl. Tolerance of cashew varieties to N dificient soils
The varieties H-1591 and M-2612 are efficient for N deficient soils. The
N use efficiency of cashew seedlings grown under pot culture was 24.7 per cent.
Exp. IV. Tolerance of cashew varieties to P deficient soils
H-1591 is an efficient variety for P deficient soils. The P use efficiency of
cashew seedlings grown under pot culture was 8.02 per cent.


Exp. V. Tolerance of cashew varieties to K deficient soils
The varieties H-1591, M-26/2 and H-1598 are efficient for K deficient
soils. The K use efficiency of cashew seedlings grown under pot culture was 12.17
per cent.
N, P and K absorption of a six month old cashew seedling was in the
order of 151.95 mg N, 21.58 mg P and 49.48 mg K per plant with a nutrient
absorption ratio of7: 1:2 (approximately).
The variety H-1591 is a super variety capable of tolerating not only
drought but also N, P and K deficient soils. The variety M-26/2 is capable of
tolerating drought as well as N and K deficiency in soils. The variety K-22-1 is
drought sensitive.