Development of Yellow Seeded Brassica napus Through Interspecific Crosses

Yellow seeded Brassica napus was developed through interspecific crosses with the two mustard species, B. juncea and B. carinata. The objective of these two interspecific crosses was the introgression of genes for yellow seed colour from the A genome of B. juncea and C genome of B. carinata into the A and C genomes of B. napus, respectively. The interspecific F₁ generations were backcrossed to B. napus in an attempt to eliminate B genome chromosomes and to improve fertility. Backcross F₂ plants of the (B. napus×B. juncea) ×B. napus cross were then crossed with backcross F₂ plants of the (B. napus×B. carinata) ×B. napus cross. The objective of this intercrossing was to combine the A and C genome yellow seeded characteristics of the two backcross populations into one genotype. The F₂ generation of the backcross F₂ intercrosses was grown in the field, plants were individually harvested and visually rated for seed colour. Ninety-one yellow seeded plants were identified among the 4858 plants inspected. This result indicated that the interspecific crossing scheme was successful in developing yellow seeded B. napus.     

Sexual hybridization between Capsella bursa‐pastoris (L.) Medik (♀) and Camelina sativa (L.) Crantz (♂) (Brassicaceae)

The development of transgenic oilseed Camelina sativa (2n = 40) and the potential for hybridization with its weedy relative Capsella bursa‐pastoris (2n = 36) necessitates a careful evaluation of the reproductive compatibility between the species. Here, we conducted over 1800 crosses (emasculation and manual pollination) to examine the ability of 10 Canadian C. bursa‐pastoris (♀) accessions to hybridize with five accessions of C. sativa (♂). Seven hybrids were confirmed among 586 putative hybrids screened with species‐specific markers, indicating a hybridization rate of 1.5 hybrids per 10 000 ovules pollinated. All seven hybrids had intermediate DNA content compared to their parents, were morphologically distinct, had low (1.9%) pollen fertility and failed to produce selfed or backcrossed seed. Given the abundance of C. bursa‐pastoris along field margins, hybrids will likely be generated in the wild, but they will be unable to establish lineages unless fertility is restored. The large number of crosses and the diversity captured by the use of multiple accessions resulted in strong statistical power and a high degree of confidence in the estimated hybridization rate.     

Wide hybridization in cowpea: problems and prospects

Summary Attempts were made to cross a wild profusely hairy cowpea (Vigna vexillata) with other cowpea types (both cultivated and non-cultivated) for the purpose of transferring gene(s) for hairiness from the wild to the cultivated genepool. No hybrid was however obtained.     

大豆亲本杂交方式对后代的遗传变异及品系产量表现的影响 Ⅰ.单交与双交的比较研究

1985—1990年用两套亲本的单、双交组合为材料,比较后代表现及选择效果,以明确双交是否较单交更优越。结果表明:单、双交组合F_2代的株高、主茎节数、单株荚数、单株粒数、百粒重、单株粒重的平均表现、标准差及变异系数无大差异。双交组合多数性状的变异幅度处在两个单交组合之间。除第二套组合双交的主茎节数同时显著少于两个单交外,其余性状均未能同时达到显著水平。按相同育种目标入选的高世代品系在生育期、抗倒伏、抗病性方面,双交均可获得与单交相似的选择效果。两个单交组合与相应的双交组合的F_4、F_5品系平均产量、20％高产品系平均产量、前二名高产品系平均产量的差异未能达到显著水平。看来,对产量进行选择,双交并不比单交更优越。     

Inheritance of resistance to anthracnose caused by Colletotrichum capsici in Capsicum

Inheritance of resistance to anthracnose caused by Colletotrichum capsici (Syd.) Butler & Bisby was studied in interspecific Capsicum populations derived from a cross between a Thai elite cultivar Capsicum annuum L.‘Bangchang’ and a resistant line C. chinense Jacq.‘PBC932′. The resistance was assessed by measuring lesion area per fruit area (LFA) on detached chili fruits, using a laboratory‐based injection inoculation. Nil symptoms resembling the resistant parent ‘PBC932’ were also identified in the progeny F₂ and BC1 populations. Segregation of resistance (nil LFA) and susceptibility in the F₂ fitted a 1: 3 Mendelian ratio, indicating that resistance was responsible by a single recessive gene. The segregation of the trait in the testcrosses in both BC1s also confirmed the 1: 3 gene segregating model as found in the F₂.     

多花黑麦草×苇状羊茅属间杂种的细胞学研究

在法国农研所吕尼西昂饲用植物育种站，通过远缘杂交以及多倍体人工诱导，获得了多花黑麦草（2X）与苇状羊茅（4X）间的三倍体、四倍体和六倍体属间杂种。这些杂种的细胞学资料表明，苇状羊茅的两个染色体组及其与黑麦草染色体组相互之间均存在着一定程度的亲缘关系；保持并利用四倍化的双二倍体是可行的，但六倍化双二倍体的前景则难以予测。总之，苇状羊茅与黑麦草染色体之间可以交换的事实得以将多花黑麦草的基因导入到苇状羊茅中，进而使后者得以改良。     

甘蔗亲本正反交对经济性状的相对效应

以甘蔗6个亲本选配8个正反交组合的F_1代为试验材料,研究了亲本品种作母本或作父本对后代7个主要经济性状表现的相对效应.结果表明母性效应对后代多数性状的表达起了重要作用.高产品种Co419作母本的后代,产量性状普遍优于其作父本的后代.高糖品种CP65-357、CP70-1133和CP72-1312作母本的组合,后代分离出高糖个体的频率明显高于作父本的组合.以综合性状好的粤农73-204作母本。后代出现的综合性状好的单株也较多.本研究结果有助于甘蔗高产高糖育种中亲本的选择和组合的选配.     

‘京白梨’与‘鸭梨’正反交后代果实性状遗传倾向研究

 以‘京白梨’与‘鸭梨’及其正反交后代为材料,研究了果实性状的遗传倾向。结果表明：‘京白梨’与‘鸭梨’杂交后代果实性状大多为多基因控制的数量性状。杂种后代果实有变小的趋势,平均遗传传递力为77.14%,平均变异系数为38.26%。果实可溶性固形物与可溶性糖都呈升高的趋势,后代平均超高亲率分别为97.25%和35.28%。正反交后代果实硬度均呈增大的趋势,平均遗传传递力为123.81%。可滴定酸有增加的趋势,平均变异系数为51.1%。果实维生素C的遗传正反交倾向不同。果实石细胞有明显增多的趋势,后代平均遗传传递力达到了182.62%。     

芸苔属植物的种间杂交研究进展

本文概略回顾６０年来芸苔属种间杂交的研究工作，分四方面进行综述：种间不亲和性及其原因；种间不亲和性障碍的克服；杂种后代的性状表现；杂种后代的利用，作者结合自己的工作展开讨论，并就杂种后代利用方面提出自己的观点。     

应用细胞质雄性不育系构建甘蓝型油菜三交杂种

在测交一代保持不育系不育特性的品种（系）称为临时保持系；将回交３－４代仍能保持不育系不育特性的品种（系）为永久保持系．前者较多，后者较少。临时保持系的研究和三交杂种的应用结果表明；三交杂种方法是克服细胞质雄性不育系微量花粉的有效途径．两个强优势的三交杂种的产量比中油８２１增产１２％以上，一个比相应的单交杂种增产２．２％，一些三交杂种的抗性得到改良。