Influence of Nut Size, Hydro Priming Duration and Storage Period on Seedling Emergence and Early Seedling Vigour Characters in Cashew ( Anacardium occidentale L.)

摘要

The influence of seed nut size, storage period and hydro priming duration on seedling emergence and early seedling vigour in Brazilian cashew biotype was investigated. Seed nuts were hand graded into three sizes - large, medium and small - and dried under ambient conditions (290 C, RH70%) for 30 days before storing them under ambient conditions for 210 days. Stored nuts were evaluated at 0, 30, 90, 120, 150 and 210 days under three different pre-sowing hydro priming hours (0, 12 and 24 hrs) for seedling emergence and vigour characters. Data collected were statistically analysed. Significant differences were found to have occurred among storage periods, hydro priming durations and nut sizes for the four seed quality characters examined. In particular, large seed nuts had the highest seedling emergence of 79% above the medium and small nuts with a marginal increase of 5 to 6%, respectively. Meanwhile, small nuts emerged earlier than the other seed nut fractions but large nuts had the longest days to emergence. Seed nuts hydro primed for 24 hrs had the best seedling emergence (79 %), reduced days to emergence (15 days) and greater seedling vigour and shoot growth. Highest seedling emergence of 80 to 81% was observed at early storage (30-90 days) and which thereafter declined to 72% at the end of 210 days, with 10% reduction. Hydro primed small nuts had significant reduction in days to emergence (12-16 days) at each storage time investigated. The beneficial effect of priming was observed in large nuts hydro primed for 24 hrs with the highest storage performance. Thus, in order to obtain good seed nut quality parameters,storage period of large nuts can be extended up to 210 days or thereafter, while medium nuts can be stored for 150-210 days but the storage duration of small nuts should not exceed 150 days under ambient conditions. In conclusion, hydro priming of cashew nuts before sowing is a possible way of enhancing seedling emergence and early vigour characters.