The Breeding Potential And Inheritant Pattern Of A Dwarf White Corn Line

As a source of important grain?seed?for part of the population and important feed?stalk?of animal husbandry in the southwestern mountainous region of China,the white corn has its unique quality,excellent adaptability and long-term green retention due to the long-term self-retaining by local people.The growing area of planting has increased in recent years.Compared with ordinary corn,the white corn plants are usually taller,more prone to lodging,and less resistant to dense planting,so the yields are generally lower.Using the local varieties of white corn as basis material,the distant hybridization,backcross and multi-generation self-crossing were carried out with the sorghum“four unlike”,and a batch of dwarf white corn was selected.This paper conducted the following study through one of the materials 8227:1.Using the 10 crosses derived from the hybridization of 8227 and 10 testers as material to analyze the combining ability of yield traits and silage nutritional quality traits.2.Using the two corn lines 8009 and 8087 with excellent comprehensive yield traits and the corn line 8003 with excellent silage quality traits,which are selected from 10 testers,to cross with dwarf white corn material 8227 to produce the 6 generations?P₁,P₂,F₁,B₁,B₂,and F₂?of direct cross and reciprocal cross,and then the genetic model of plant height,ear height and WSC in 6 generations of direct cross and reciprocal cross were studied in multi-environment.In order to find out the genetic pattern of the plant height,ear height and WSC of dwarf white corn line 8227and its breeding potential,and the following results were obtained:?1?The combining ability effect value of plant height and GYP of dwarf white corn line 8227 was-2.77and 21.84 respectively,the combining ability effect of comprehensive yield trait was better,crossed with other excellent inbred lines,the dwarf stalk,lodging-resistance and high-yield varieties can be obtained.In addition,the combining ability effects of NDF and ADF of the corn lines were 1.12 and 0.84,respectively,and the combining effects of traits such as DW,WSC and IVDMD were-9.76,-0.65 and-1.73,respectively.The combining ability of biological yield and silage nutritional quality traits was poor.?2?The dwarf white corn line 8227 crossed with the corn lines 8003,8009 and 8087with better comprehensive traits,can obtain the dwarf stalk,lodging-resistance and high-yield varieties of 8227×8003,8227×8009 and 8227×8087,whose plant height,ear height and yield were 257.5m,100.1m and 8544kg/hm²;254.1m,102.5m and 7222.5kg/hm²;256.6m,104.1m and 7915.5 kg/hm²,respectively.Among them,8003 has better silage nutritional quality crossed with 8227 could obtain a variety of 8227×8003,and whose NDF,ADF and CP contents were 54.5%,24.4%and 8.6%,respectively,reaching the national silage quality third,second and first level standards respectively.And the value of DW and IVDMD were also hight at 1.4×104kg/hm² and 64.6%,respectively.?3?The plant height of the 4 crosses of 8227×8009,8009×8227,8227×8087 and8087×8227 were in accordance with the mixed genetic modle of D,E-1,D and D-3 in Xinjin,respectively;and of E-1,D,E and D in Ya'an,respectively;and of E,E-1,D and E-3)in Zigong,respectively.The ear height was consistent with the genetic modle of D-4,E-5,D and D in Xinjin,respectively;and of E-1,E-1,D and D in Ya'an,respectively;of B-1,D,D and E-3 modle in Zigong,respectively.The plant height and ear height of the 12crosses were generally in accordance with the major gene+polygene mixed genetic model.?4?The plant height and ear height are mainly based on major gene inheritance,supplemented by polygene gene.The dominant effect is dominant,the additive effect is second,and the episode was in high frequency of occurrence.The stability of the two traits in each cross was better and should be selected in the early generation.Among the orthogonal crosses of 8227×8009 and 8227×8087,the highest selection efficiency was in B₁ and F₂ generations,and in B₂ and F₂ generations in the reciprocal cross.In addition,the genetic model of plant height and ear height was influenced by experimental materials,environment and maternal effects.In the analysis of genetic modle of these two traits,attention should be paid to the choice of materials and environment,as well as the effect between orthogonal cross and reciprocal cross,in order to make a correct analysis of the inheritance of plant height and ear height.?5?The water-soluble carbohydrate?WSC?of the cross of 8227×8003 and 8003×8227 was in accordance with the genetic modle of D?1 pair of additive-dominant major genes+additive-dominant-epistasis polygene genes?and E-1?2 pairs of additive-dominant-epistasis major genes+additive-dominan polygene genes?,respectively.There were additive and dominant effects,and the epistasis effect was also in existence.In addition,the maternal effect was in the inheritance of WSC.