不同栽培条件对小麦杂种后代性状表现的影响

采用4种不同的栽培方式,探讨了杂种F_2代的性状分离和选择效果。结果表明,适当地增加种植密度和改善肥水条件,有助于抗性和丰产性诸性状的遗传变异更好的得以表达,进而达到提高性状鉴定和选择效果之目的。本文结合有关育种理论,对如何创造有效的性状鉴定条件和多种杂交后代处理办法的结合作了讨论。     

Effects of high- vs. low-yield environments on selection for increased biomass yield in switchgrass

No information is available on the effects of different biomass yield environments on selection efficiency in switchgrass (Panicum virgatum L.) breeding improvement. This study was conducted to assess the effects of high- and low-biomass yield environments (HYE and LYE, respectively) on recurrent selection for general combining ability (RSGCA) in a lowland population of switchgrass (NL-94). The top 14 of 65 NL-94 C₀ parent plants were selected based on biomass yield of half-sib (HS) progeny tested for one post-establishment year under HYE and LYE conditions. Nine of the 14 C₀ parent plants were the same based on HS performance under HYE and LYE. Selected plants were intercrossed to produce NL-94 HYE and NL-94 LYE C₁ populations. One hundred and twenty-five HS C₁ progeny families (60 NL-94 HYE and 65 NL-94 LYE) were evaluated for biomass yield for 3 years (2002–2004) under HYE and LYE conditions. The HYE produced about 2.5 times higher biomass yields than the LYE in both C₀ and C₁ HS progeny tests. Estimated additive genetic variance and predicted gains from selection (ΔG) were high in the C₁ populations indicating that RSGCA should achieve higher biomass yields. Mean biomass yields of C₁ HS families originating from the LYE protocol were significantly higher than those of families originating from the HYE protocol in both HYE and LYE performance tests, suggesting greater selection response under LYE in the C₀ population. The estimates of narrow-sense heritability ( ) and ΔG from the C₁ populations indicate that positive response to selection for biomass yield is possible in subsequent cycles of selection under either HYE or LYE, with a possible small advantage for HYE.     

水稻广亲和品种与籼、粳稻的亲和力遗传分析

分析了广亲和品种02428,CP—SLO_(17)和轮回422与籼、粳稻杂种F_1、F_2及F_3世代亲和力与颖尖色的遗传特点,结果表明,具有一个广亲和品种的组合,F_1花粉育性与结实率正常,均在70%以上,F_2结实率呈连续变异,但主要分布在60～80%区域,平均结实率65.1%,F_3育性变异度与F_2基本一致,但平均结实率有明显提高。两个广亲和品种间杂交后代育性显著提高,F_2结实率低于60%的单株较少,而不含广亲和品种的组合F_1表现半不育,F_2呈正态分布,平均结实率43.4%,主要分布在40～60%之间。以上说明广亲和基因是存在的,广亲和力既受主效基因支配,也有微效基因参与作用。颖尖色出现3∶1或9∶7分离,有色颖尖与高结实率连锁明显,因此,颖尖色可以作为选择广亲和基因的标记性状。     

间作大豆产量与主要经济性状的相关及选择

在间作条件下，测定和估算了栽培大豆产量与主要经济性状间的相关，回归，遗传进度和选择指数等遗传参数。结果表明，除百粒重与小区产量呈负向回归和相关外，其余８性状与小区产量均为正向关系。     

大豆抗SMV_1、SCN_3基因聚合选择方法的研究

采用抗大豆孢囊线虫 3号生理小种SCN3 和大豆花叶病毒 1号株系SMV1的大豆品种互交 ,F1F5用 5种不同选择方法 ,产量LSD 0 .0 5测定处理间表现为A、B、C三个等级 ;不同选择方法的 6个产量性状变异系数差距大。SCN3 和SMV1双抗性基因RSVRSN互作对产量具有累加增产效应达 8% 35 .9% ,品系产量和品系抗性基因聚合数量呈极显著正相关 (r=0 .972 )。不同选择方法F5RSVRSN出现率 0 % 10 0 %。双接种法或交叉接种法F5RSVRSN出现率 10 0 % ,株系间变异大 ,结合异季南繁加代 ,是较好的选择方法     

小麦抗赤霉病轮自选择育种

本文论述了运用太谷核不育小麦进行抗赤霉病轮回选择的基本程序、育种效果和今后展望，为培育抗赤霉病的丰产品种指出了一条新途径。     

杂交大豆杂优豆1号选育

杂优豆1号(皖豆25号)是安徽省农科院作物所1997年以M型质核互作雄性不育系W931A与恢复系WR016组配的杂交大豆新组合,这是世界上第二个通过正式审定、可进行产业化开发的大豆杂交种.2002-2003年参加安徽省夏大豆品种区域试验,两年平均产量191.16 kg/667m2,比CK中豆20增产15.37%,均达极显著水平.2003年参加安徽省夏大豆品种生产试验,平均产量177.28 kg/667m2,比CK中豆20增产19.14%.在多年多点试验示范中表现抗病、高抗倒伏、高产稳产的优点,蛋白质含量43.56%,脂肪含量18.96%,生育期111 d,商品性好,适于安徽省淮北及江淮地区作中熟品种种植.     

玉米品系内改良S1选择方法与技术

根据玉米群体轮回选择的基本原理和方法，建立起一套简单易行的群体改良S1选择方法，其主体技术包括组建一个好的基础群体，利用控制授粉提高优良基因的频率，借助互交使基因重组。采用此方法对CIMMYT提供的热带玉米群体进行了3轮选择，群体产量平均每轮增益为6．4％，群体测交种产量平均每轮增益为6．3％。表明群体产量的一般配合力有较大的提高。     

花生主要经济性状遗传参数对单株产量的选择效果

本文估算了花生11个性状的遗传进度和选择指数等遗传参数。结果表明,性状间遗传力存在较大差异,应据此掌握各世代不同性状的选择标准。对单株产量的直接选择很重要,单株结果数是相关选择的关键性状,选择饱果数多、侧枝长的材料对单株产量也有一定的改良效果,选择时应予以重视,而百果重、百仁重不是产量的限制因素。花生育种应用选择指数方法进行综合选择比对单株产量单一性状直接选择的效率提高23.22％,应用前景广泛。     

An international panorama of goat selection and breeds

The preservation of the biodiversity of animal breeds is an important condition to maintain the ability of animal production to adapt to the changing conditions of breeding and production systems in the future. The decrease of the number of animal breeds has been observed both for sheep, cattle and goats in relation with the standardisation and intensification of animal production systems.Goats are mainly concerned by the situation as they have the biggest increase in livestock numbers in 20 years. A global overlook of goats worldwide is showing a contradictory situation: On one hand, small but well organised sectors have developed in a few countries for milk and cheese, meat and fibre production. On the other hand, most of the goats are mostly still used for auto consumption of milk meat and skin or fibres in village herds. The present goat genetic situation is the direct consequence of this evolution with the high specialisation of a small number of selected and well characterised breeds for milk, meat and fibres and a majority of not well defined populations and local breeds, generally without selection schemes and organisation.A global panorama of the main families and breeds is presented. A special consideration is then pointed on the necessary financial and logistic conditions to achieve successively these selection objectives. After having observed that in many cases these conditions are not present, this report concludes by some proposals to control better the possibilities of success and express with more efficiency the genetic potentiality of this interesting species.