Analysis Of Genetic Effects On Main Economic Traits And Study On Floral Bud Differentiation And Chemical Control Of Luffa

Recently, requirements of new luffa cultivars have been increasing gradually with increasing of luffa cultivation area year by year. Yet the work on luffa breeding carried out relatively late, which had few research on basic breeding theory, such as heterosis, genetic effect and correlation analysis between main economic traits. The purpose of this experiment is to investigate heterosis and genetic effects of main economic traits, find out correlative traits with yield and earliness and importance of every correlative trait, thereby afford theoretical guide to luffa breeding. Furthermore, luffa is a kind of monoecious melon crop. The appearance time and numbers of male flowers and female flowers are very correlative with yield and earliness directly. There sometimes was a problem that yield decreasing caused by different opening time between male flowers and female flowers in protected cultivation. Therefore, it has important meanings for guiding practice that study on the floral bud differentiation and chemical control on sex expression according to the flower sex forming time.This experiment selected six parents from luffa (L.cylindrica Roem.) population at random and got 15 F1 hybrids via diallel cross design. The results got by investigation and statistics analysis on 18 economic traits in field and laboratory, and observation on floral bud differentiation process of two material with different earliness are as follows.1. F1 hybrids of luffa performed heterosis obviously. Heterosis of the early yield, the early plant height, the node lengths the total yield, the single fruit weight, the first node of female flower and the rate of fruit development were performed at a relatively high level. The percent of cross combinations with positive heterosis over mid-parents of total yield was 86.7 % ,over better parent was 66.7%. The percent of heterosis cross combinations of the content of soluble sugar, soluble protein and dry substance were low, and heterosis of this three quality traits were relatively low.2. The studies of genetic effect showed that inheritance of the first node of female flower, the early leave numbers, the node length, the rate of fruit length development, thesingle fruit weights the fruit length, the fruit diameter and the fruit shape index were controlled by additive and dominant effect together. The inheritance of the early plant height, the early yield and total yield were controlled by dominant effect, and environment effect of the latter two were also significant. The fruits number, the rate of fruit diameter developments the content of soluble sugar, the content of dry substance and the female flowers numbers were controlled by additive effect, and the fruits numbers, the content of soluble sugar and the female flowers numbers were also affected by environment significantly. The heritability of the fruit shape index, the fruit length and the fruit diameter were the greatest among all traits, the broad-sense heritability of the early yield and the content of soluble protein were the lowest; the narrow-sense heritability of total yield, the early plant heights the early yield and the content of soluble protein were the lowest.3. The results of correlation analysis showed very significant positive correlation between the early yields the single fruit weight, the fruits numbers and the total yield. The results on path analysis revealed that the total yield was affected mainly by three agronomic traits, includes the fruits numbers, the single fruit weight, and the fruit length. The multiple regression analysis showed the fruits numbers and the single fruit weight were the key component traits of total yield. Therefore, these two traits could be taken as main selection traits for high yield. The very significant positive correlation were found between the early yield and the female flowers numbers, the early plant height, significant positive correlation between the early yield and the early leave numbers, very significant negative correlation were found between the early yield and the first node of...