Genetic Analysis Of Heat Tolerance In Cucumber

Cucumber is an important vegetable plant, its fruit is delicious, full of nutrient and is cultivated in the world wide .In 1970s our country has been the country with the highest planting area and production in cucumber.Cucumber is fond of warm, but does not tolerant high temperature. In high temperature, cucumber will have decreasing production and bad commodity and weak stress tolerance ability. With the increasing global green house effect, the climate turn warm gradually, the research of heat tolerance in vegetable has been paid more attention, especially as the vegetable plant with the biggest cultivation area in protected culture the research on cucumber heat tolerance is more importance. The experiment studied the heat tolerance of the provide parents, test the index of heat tolerance identification, test positively the separation in F2 generation heat tolerance, and the genentic model of cucumber heat tolerance. Estimate the genetic parameter and gene effect, which provide principle base for heat tolerance research in cucumber.The mostly production of study:(1)The research analyse the length of radicle of cucumber seed treated with high temperature in germinating period, the content of MDA, the activity of catalase, the accumulating content of proline in seedling stage, cytoplasm membrane heat stability, and the change ratio of production in mature stage. There is good relativity between the identification index and heat tolerance, which could be looked as the reference index of cucumber heat tolerance identification. The research choose the heat tolerance stability of cytoplasmic film as the identification index of cucumber heat tolerance genetic analyse.(2)The normal distribution test of cucumber F₂ generation heat tolerance shows that heat tolerance in cucumber F₂ generation present continuity variance and obey the normal school.Heat tolerance of cucumber is quantity genetic controlled by multiple gene and controlled by major gene.(3) The test result of heat tolerance genetic model in cucumber shows that heat tolerance obey the additive -dominance genetic model, additive effect plays the main role ,and dominance effect plays the lesser role, no epistasis effect exists. Compared with the dominance variance, environmental variance is more important and cucumber is more easily affected by environment. Broad heritability and narrow heritability are higher in heat tolerance of cucumber.