Disciplines Of Fruit-set Success And Triploid Induction Of Hevea Brasiliensis

In this thesis, induction of diploid female gametes by high temperature with a patent "heating apparatus"(ZL200610113448.X) was studied based on the reproductive biological results of Hevea brasiliensis Muell. Arg. Major results as follows,(1) The clone GT1was able to produce unreduced female gametes naturally. After seeds from GT1was collected and sown to the nursery,419seedlings grown and3triploids were detected by Flow cytometry, showed that unreduced female gametes were produced by the GT1, with frequency of0.72%. In addition, eight haploids and3nullisomics were obtained, whose frequencies of occurrence were1.91%and0.72%respectively.(2) There are development process correlations between different staminate flowers in the same inflorescence. In the same part of the inflorescence, the second class of staminate develop into the process of meiosis while the first class of staminate enter meiosis diakinesis; the second class of staminate develop to the end of the leptotene while the development of first class of staminate into the tetrad-spores period; when the first class of staminate develop into pollen mononuclear period, the second class of staminate flowers into pachytene-tetrad period and the third class of the staminate develop into the lepotene. Development process correlation also exist in the staminate flowers which in different class and different part of inflorescence, the development process of male flowers in the lower and middle part of inflorescence are similar, which makes the contours of the development process a triangle.(3)Development process of pistillate flowers in the same inflorescence are the same, while the development process of pistillate flower and staminate flower have corresponding relation, which also correlated with the external morphology of the inflorescence. When staminate flowers in the lower part of inflorescence developed into leptotene-tetrad period, pistillate flowers in a period of megasporocyte; when staminatc flowers developed into microspore-microspore with central nucleus period, pistillate flowers in a period of meiosis; when the staminate flowers developed into microspore with central nucleus to mono-nucleate microspore at late stage period, pistillate flowers in a period of uni-nucleate embryo sac to two-nucleate embryo sac; when a very small number of staminate flowers elongated and turned yellow, pistillate flowers developed into two-nucleate embryo sac to four-nucleate embryo sac period; when a few of staminate flowers blooming, pistillate flowers developed into the period of eight-nucleate embryo sac; pistillate flower developed into mature embryo sac structure when elongated and turned yellow. The process of female gametes could judged instantly with the development process corresponding relation between pistillate flower and staminate flower, which make the induction of female gametes chromosome doubling by high-temperature easy.(4) There were significant differences in number of pistillate flowers, locations of pistillate flowers on panicles and number of panicles in fruit-set branches among different cultivars. Similarly to the distribution of fruits on panicles, pistillate flowers distributed on the top or lower positions of panicles. Pistillate flowers which could produce fruits were mainly located on the lower positions of the fruit-set branches. The probability of fruit-set decreased with the distance between panicles and trunk increasing. Thus, based on the disciplines of pistillate flowers distribution, fruit-set panicles and fruit, the efficiency of crossbreeding could be improved by pollinating panicles on the fruit-set branches with higher fruit-set rate and synchronously thinning pistillate flowers with lower fruit-set rate.(5)Fifteen triploids were produced by female gametes chromosome doubling with high-temperature. Use the heating apparatus, pistillate flowers of three varieties (rubber tree GT1. RRIM600and RRII118) were treated with high temperature. After pollinated naturally,13triploids were obtained from the offspring of GT1, the highest frequency was33.33%, the average frequency was1.79%; two triploids were obtained from control group, the highest frequency was0.71%.