Hand pollination of Hevea brasiliensis in Nigeria (1984-1990). comparison with open pollinated field data

Abstract

Artificial hand polinations of Hevea brasiliensis were done at the Rubber Research Institute of Nigeria (RRIN) from 1984-1990: these involved 28,887 female flowers from which only 7.60perc. mean fruit set was obtained while only 5.13perc. of the flowers formed fruits that reached maturity. A correlation value of 0.65 was obtained between number of female flowers pollinated and fruits set. Clonal variations were observed for flowers production in the open pollinated field with very high correlation of +0.9 between male and female flowers. Clones PB 5/51 and RRIM 707 produced the highest number of both male and female flowers. The mean male to female flower ratio was 14.1. Male flowers had a higher correlation coeffieciency of r=0.32 with fruit set than emale flowers with r=0.05. An estimate of 15perc. fruit set was obtained under natural open field pollinations in 1989 while only 8.8perc. of the flowers formed fruits that reached maturity. Only about 64perc. of the 64 perc. of the fruits set under both artificial and natural open pollinations reached maturity. While about 36perc. abortions of fruits took place. The implications of these results are discussed.