RRI Publications
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Item Preliminary observations on flowering, pollen germination and fruit-set in Hevea species(Rubber research Institute. Agalawatte, 1984) Attanayake, D.P.S.T.G.; Dharmaratne, S.C.The low fruit set following hand pollinations is a hindrence to rapid progress in Hevea breeding. Observations were made on flowering time, it's effect on pollen collected after anthesis were observed in this preliminary work.Item Gas exchange parameters for early selection of Hevea brasiliensis Muell. Arg(Rubber Research Institute. Agalawatte, 1985) Nugawela, A.; Aluthhewage, R.K.Selecting high yielding progeny from Hevea breeding programmes is a money and time consuming approach and limits the progress of breeding, Girth, bark thickness, numberof lates vessel rings, latex vessel density and first few years yield of 7-8 year old Hevea budding are reported to be correlated to the yield potential. These parameters are used by some breeeders for a primary selection using smalle scale clone trials. Latex is biosythesised from sucrose in latex vessels and the potential of sucrose supply to latex vessels depends on CO2 assimilatory capacity of the canopy and the partitioning of assimilates. Attempts were made to estimate the mean CO2 assimilatory capacity of a healthy and a matur eleaf whole in year old Hevea clonal buddings. Preliminary studies show the mean CO2 assimilatory capacity of a whole and its ratio with water use efficiency value to be correlated qith yield potential. These observation suggest that effective selection of clones for further testing in large scale clone trials could be done on this basis, when buddings are around a year old.Item Hand pollination of Hevea brasiliensis in Nigeria (1984-1990). comparison with open pollinated field data(Rubber Research Institute. Agalawatta, 1990) Olapade, E.O.; Omkhafe, K.O.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.Item A method of inducing floral stimulus for early flowering of Heavea brasiliensis(Rubber Research Institute. Agalawatta, 1959) De Silva, C.A.; Chandrasekera, L.B.