Study On Relationship Among Heterosis,Combining Ability And Genetic Distance Of Three-way Cross Of Momordica Charantial

Momordica charantia L was produced in the East India and were introduced to Europe after the 17th century.They are used for ornamental purposes and are now cultivated in many parts of the world.The bitter gourd is fruity and can not only be eaten as a dish,but also used as a medicine.It has the effects of detoxification,hypoglycemia,nourishing blood and nourishing liver.At present,the domestic bitter gourd breeding units mainly produce high-quality,high-yield F1 products for screening the homozygous lines of the bitter gourd.The work is large,the purpose is single,and the chance of obtaining high-quality bitter gourd varieties is not high.Three-way cross Breeding generally has improved breeding traits,improved stress resistance,reduced seed production costs,and other breeding advantages.Three-way cross Breeding was first applied to maize breeding,and later applied to crops such as rice,soybeans,rape,non-heading Chinese cabbage,and green onions.However,there are no reports on the basic theories of bitter gourd breeding at home and abroad.Therefore,in this study,15 hybrid combinations were prepared from 11 inbred high-generation indica inbreds by incomplete double-crossing and the heterosis and combining ability of 10 quantitative traits such as yield,melon length and melon diameter in the three cross combinations were analyzed.The genetic effects of agronomic traits were measured by SSR molecular markers to determine the parental heritage distance,and the correlations of trait performance,heterosis,mating ability and parental genetic distance were analyzed.The conclusion was:1.In the three-cross hybrid traits,the heterosis of yield and melon picking was more prominent,positive and stronger,and the variability was smaller.Through hybridization,a stable high-yielding,high-yielding three-cross hybrid could be obtained;the heterosis of the first female flower was not obvious,but the variability is extremely large.Parents can be selected to obtain early-maturing or late-maturing three-line varieties.The trend of parental and super-parent parenting in each trait was similar,indicating that there was a certain link between the traits,and the correlation between the traits could be further analyzed.2.Generalized heritability:first female flower node>melon number>ste-m diameter>melon flesh thickness>melon length>leaf width>single melon weight>leaf length>melon diameter>yield;narrow sense heritability:melon number>melon length>first female flower node>single melon weight>stem diameter>melon diameter>leaf width>leaf length>melon flesh thickness>yie-1d,in which the narrow heritability of melon number and melon length exceeds 50%,indicating the additive inheritance of these two traits.Large reffect,stable inheritance to offspring.3.The genetic distance ranges from 0.3449 to 0.8428 with an average of 0.6260.Among them,the genetic distance between Q2Q5 and Q3Q6 was the largest,and the genetic distance between P5 and Q1Q4 was the smallest.Eight balsam pear parents were divided into four groups:the first group had 1 balsam parent,which was P1;the second group had 3 balsam parents,which were distributed in 2 subgroups.The III subgroup included P2,P4,and 112.The group includes P5;the third group has 2 balsam pear parents,including P3 and Q1Q4;the fourth group has 2 balsam pear parents,including Q2Q5 and Q3Q6.4.There was a significant positive correlation between the parental advantage of the yield and the genetic distance of the parents.Except the yield and number of fruit picking,the heterosis of the other parents had no correlation with the parental genetic distance.SCA analysis of the yield traits and the genetic distance of the parents have a certain positive correlation,that is,the farther the parental kinship,the yield of the selected three-cross combination may be higher;by analyzing the kinship of parents,the yield traits and the pros and cons of the main arbor stems in the progeny of three crosses can be predicted;other quantitative traits such as fruit picking,single fruit weight,etc.can hardly achieve predictability through parental kinship.