芸芥与芸薹属属间杂交亲和性研究

选用 5个芸芥与 6个芸薹属种进行杂交 ,研究了芸芥与芸薹属属间杂交的亲和性 ,试验结果表明 :芸芥与芸薹属的远缘杂交属于高度不亲和 ,结角率为 2 .76 % ,结籽率为 1.35 %。影响其杂交亲和性的因素有杂交亲本基因型、杂交组合方式 ,其中以芸薹属作母本的杂交亲和性要高于以芸芥作母本的组合的杂交亲和性。     

芥蓝×诸葛菜属间杂种的获得

用子房培养和胚培养相结合的方法,获得了芥蓝×诸葛菜属间杂种。授粉后１４ｄ和１８ｄ的子房在附加ＩＡＡ２ｍｇ／Ｌ和ＫＴ０．５ｍｇ／Ｌ的ＭＳ培养基上培养,结籽率分别为５４．３％和４６．２％。在附加ＩＡＡ０．２ｍｇ／Ｌ和ＫＴ２ｍｇ／Ｌ的ＭＳ培养基上,种子萌发率为１３．３％。其Ｆ１形态介于双亲之间,花粉无活力,开放授粉不能结籽,染色体数为２１,是双亲单倍染色体数目之和。     

58份南瓜杂交组合果实性状调查与分析

对58份南瓜(Cucurbita moschata Duch.)杂交组合(F1)的主要果实性状进行了测定与分析。结果表明,不同杂交组合的性状差异较大,其中果肉厚度为1.4~5.4 cm、果形指数为0.7~4.0、可溶性固形物含量为8.9%~16.9%;果皮主色大部分为土黄色,果肉颜色多为深黄和浅黄色,果肉肉质以中等致密和疏松为主、综合品质属中等。58份组合的果实产量最高的是009-1×浙江七叶组合(2 756.9 kg/667 m2),产量最低的是450×十姐妹组合(182.8 kg/667m2),平均产量为828.4 kg/667m2。该结果为南瓜新品种选育提供了依据,并在理论与实践上对今后的南瓜育种工作提供了一定的指导借鉴。     

玉米温热杂交种光周期敏感相关性状的遗传模型研究

【目的】分析玉米温热杂交种的光周期敏感特性及相关性状的遗传模型。【方法】以9份北方温带选系和8份含热带、亚热带种质的南方选系,按NCⅡ设计组配72个温热杂交种,分别在北京和雅安进行田间试验。【结果】供试温热杂交种总体均表现出较强的光周期敏感性,ASI等10个性状为温热杂交种光周期敏感性相关性状。其遗传模型大多数符合加性-显性遗传模型,少数属于加性-显性-上位性遗传模型;多数性状以加性效应为主,非加性效应为辅,随着日照变长,加性效应的主导地位更加突出。【结论】将热带、亚热带玉米种质利用于温带玉米遗传改良及育种时,应注重相关性状的加性基因效应。     

系谱追踪等位变异法分析籼粳交亲本对衍生后代的遗传贡献

利用16个亲本及特异种质92gk729的39个衍生品系为材料,采用221对SSR标记和系谱追踪等位变异法分析祖先亲本在籼粳杂交各衍生世代的遗传贡献。结果表明：（1）在92gk729中有10对SSR引物位点上出现4个祖先亲本杂交重组的特异条带,有5个重组后的特异位点能稳定传递到衍生后代中,有1个重组后的特异位点在亲本及衍生品系中都没有出现;（2） ketan Nangka、嘉南粳、02428、明恢72对92gk729的遗传贡献率分别为15.09％、21.32％、22.78％和34.64％。4个亲本杂交染色体片段重组后能产生新的特异位点,其遗传贡献率是6.17％;（3）4个祖先亲本在每条染色体上对衍生后代遗传贡献的趋势都是随着衍生代数的递增,遗传贡献率逐渐下降。亲本对各世代衍生品系的遗传贡献率为明恢72＞02428＞嘉南粳＞Kenta Nangka ;（4）采用系谱追踪等位变异法进行数据分析,然后对数据进行聚类,发现同一杂交组合的品系、同一系谱分支存在衍生关系的大部分品系聚为一类,后代亲缘关系相近的高代材料聚为一类。说明该法能够较好地反映祖先亲本对后代的遗传贡献。     

Production of doubled haploids in triticale (×Triticosecale Wittm.) by means of crosses with maize (Zea mays L.) using picloram and dicamba

The aim of the present study of triticale × maize crosses was to find an appropriate growth regulator treatment to improve the yield of triticale haploids and the subsequent production of doubled haploids. The growth effect in unpollinated ovaries of triticale was examined after treatment with 1000 mg/1 indole-3-acetic acid (IAA) or 100 mg/1 solutions of the following auxin analogues: 2,4-dichlorophenoxyacetic acid (2,4-D), 3,6-dichloro-o-anisic acid (dicamba), 4-chloro-o-tolyloxyacetic acid (MCPA), phenylacetic acid (PAA), 4-amino-3,5,6-trichloropicolinic acid (picloram) and 2,4,5-trichlorophenoxyacetic acid (2,4,5- T), respectively. Dicamba stimulated growth of the ovaries significantly more than picloram and both stimulated more growth than the other growth regulators tested. Neither dicamba nor picloram induced embryo development in unpollinated pistils. Dicamba and picloram solutions, at concentrations of 25, 50, 75 and 100 mg/1, were subsequently applied to pistils of triticale pollinated with maize. On average, between 17.1 and 21.5 embryos/100 fiorets were excised after treatment with 75 or 100 mg/1 solutions of picloram or dicamba but the concentrations of 20 and 50 mg were less effective. The frequencies of excised embryos did not differ between genotypes. Seventy-six green haploids were obtained from 100 embryos rescued in vitro on the 190–2 and modified B5 media, the first medium being superior. The plants were subjected to colchicine treatment at the 3–4 tiller stage. Out of 68 plants brought to maturity, 25 exhibited fertile sectors. In comparison with previous studies, picloram and dicamba significantly improved the efficiency of the triticale × maize crossing. The low dependence on the mother germplasm makes triticale × maize crossing an efficient alternative to the androgenetic methods of doubled haploid production in triticale.     

Current status and future strategy in breeding chickpea for resistance to biotic and abiotic stresses

Chickpea (Cicer arietinum L.) production has remained static for the past two decades. One major limiting factor has been susceptibility of cultivars to several biotic and abiotic stresses that adversely affect yield. In recent years, cultivars resistant to Ascochyta blight (Ascochyta rabiei [Pass.] Lab.), Fusarium wilt (Fusarium oxysporum f. sp. ciceris), and cold have been bred and released in many countries. Some progress has been made in breeding for resistance to drought, insects, and cyst nematode, but not for viruses, heat, and salinity. Two or more stresses are of equal importance in most chickpea growing areas. Therefore, future efforts should be directed toward the development of cultivars with multiple-stress resistance. Proper understanding of important stresses in different countries and the genetics of resistance should lead to more systematic approaches to resistance breeding. Wild Cicer species hold promise and deserve attention in resistance breeding.     

Wide compatibility in rice (Oryza sativa L.)

Summary Wide compatible varieties (WCVs) show normal spikelet fertility in crosses with Indica and Japonica rice varieties. Crosses of Indica and Japonica varieties frequently show high spikelet sterility which prevents exploitation of heterosis for grain yield. We screened 41 rice varieties for the wide compatibility trait by crossing each with three Indica and three Japonica testers. Varieties giving fertile F₁ hybrids with both groups of testers were classified as WCVs. Seven varieties viz., BPI-76 (Indica); N 22; Lambayeque-1 and Dular (Aus); Moroberekan, Palawan and Fossa HV (Japonicas), were identified as WCVs. The frequency of WCVs was higher among Aus and Japonicas. The wide compatibility trait in varieties: Dular and Moroberekan was controlled by a single dominant gene linked with the Est-2 and Amp-3 loci (mean recombination 32.0%). Est-2 and Amp-3 showed complete linkage. Pgi-2 was found to be linked with Est-2 and Amp-3 (mean recombination 16.1%). Est-2 and Amp-3, showed a tighter linkage with C ⁺ (mean recombination 4.1%). Pgi-2 showed a lower linkage with C ⁺ (mean recombination 17.3%). The recombination values between the WC gene in Dular and C ⁺ was much higher than those reported in Japan for the WC gene (S₅ ⁿ) from Ketan Nangka. It is possible that the WC gene from Dular is different from that in Ketan Nangka. Linkage intensities with the WC gene were not strong enough to be of use for indirect selection for the wide compatibility trait. A search for a more closely linked isozyme or DNA marker was proposed.     

Genetic analysis of resistance to root-lesion nematode (Pratylenchus thornei) in wheat

The inheritance of resistance to root‐lesion nematode was investigated in five synthetic hexaploid wheat lines and two bread wheat lines using a half‐diallel design of F₁ and F₂ crosses. The combining ability of resistance genes in the synthetic hexaploid wheat lines was compared with the performance of the bread wheat line ‘GS50a’, the source of resistance to Pratylenchus thornei used in Australian wheat breeding programmes. Replicated glasshouse trials identified P. thornei resistance as polygenic and additive in gene action. General combining ability (GCA) of the parents was more important than specific combining ability (SCA) effects in the inheritance of P. thornei resistance in both F₁ and F₂ populations. The synthetic hexaploid wheat line ‘CPI133872’ was identified as the best general combiner, however, all five synthetic hexaploid wheat lines possessed better GCA than ‘GS50a’ The synthetic hexaploid wheat lines contain novel sources of P. thornei resistance that will provide alternative and more effective sources of resistance to be utilized in wheat breeding programmes.