Reproductive biology of teak (tectona grandis linn.f.) in East Java, Indonesia
Date
1996
Authors
Palupi, Endah Retno
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Abstract
Reproductive biology of teak (Tectona grandis Linn. f.; Verbenaceae) in a CSO in East Java, Indonesia was investigated. The causes of low fruit and seed set were identified. Fruit maturation in relation to the low fruit germinability was studied. Three clones, representing low, intermediate and high fruit production capacity, were selected for the study. Clone 5 (low fruit-production capacity) was early flowering. Its peak flowering period started before the CSO peak-flowering period and coincided with the peak rainy season. Clone 12 (intermediate fruit-production capacity) was a late flowering clone. The peak flowering period was reached toward the end of the CSO peak flowering period and after the peak rainy season had passed. Clone 17 (high fruit-production capacity) had peak flowering that coincided with the CSO peak-flowering, toward the end of the peak rainy season. The reproductive success of clone 5 (0.1 % ) was lower than clone 12 (0.4%) and clone 17 (0. 5% ), although clones 5 and 17 had a higher mean numbers of flowers per in.florescence (1948.1 and 2007.2 FL/Infl, respectively) than clone 12 (1331.6 Fl/Infl). In general, low fruit and seed set were the major constraints in fruit production. However, since one seed per fruit is more desirable, the low seed set is not considered to be a problem. That left low fruit set as the major problem.
Fertilization occurred within 24 h after flower opening (AFO). Thus, flowers that aborted after 24 h AFO were considered as fertilized. Percentage of pistils remaining 48 h AFO for clones 5, 12 and 17 were 30, 42.5 and 40%, respectively. The mean numbers of fruits per inflorescence at maturity for clone 5 was 10.375 (0.5%), clone 12 was 17.875 (1.3%) and clone 17 was 35.563 (1.8%). The abortion of fertilized pistils occurred during seed and fruit development and maturation. A major cause of seed abortion was abnormal development of endosperm. During early stages of development this caused the zygote to abort. In later stages it restricted embryo development, causing seed abortion. Failure in endosperm development may result from a high incidence of self-pollination. Clonal variation did not affect fruit quality, but maturation stage did. Fruit collected at 24±1 w AFO (M-3), when fruit water content was about 11%, gave the highest germination capacity (57.67%). The germination value of fruit at M-3 was also higher than M-1 (16±1 w AFO) and M-2 (20±1 w AFO). Although these fruits germinated slower than fruits collected at 28±1 w AFO (M-4), the higher germination capacity is more advantegous.