Geographical, altitude and agro-ecological differentiation of isozyme and hordein genotypes of landrace barleys from Ethiopia: implications to germplasm conservation

An analysis of the variability of genes encoding six isozyme systems (15 loci) and two storage proteins (2 loci) in landrace barley from Ethiopia is reported. The materials consisted of populations collected from sites as low as 1650 and as high as 3750 meters, covering a wide range of agro-ecological conditions and geographical areas. Of the 17 loci 7 were polymorphic and 10 monomorphic when the 95% criterion of polymorphism was applied. Despite the disproportionate monomorphic loci, polymorphism was detected in all populations when this criterion is used. The populations were found to possess fairly low mean number of alleles per locus (A = 1.5), low mean value of expected heterozygosity (H = 0.134) and a fairly high mean percentage of polymorphic loci (P = 35.3%). The mean F_ST= 0.474 for the populations is typical of inbreeding species. The result indicated that allelic richness is concentrated in altitude class 3 (2500–3000 m) followed by altitude class 1 (<2000 m). Altitude class 2 (2000–2500) holds an intermediate place though it is the highest in terms of expected heterozygosity (H = 0.245). Higher genetic diversity is concentrated in some geographical regions such as Shewa, Arsi, Bale compared to others (Welo, Gamu Gofa, Gojam). Genetic differentiation among the agro-ecological zones was more profound than both among the altitudes and among regions. Correlation analysis between phenotypic diversity (Shannon-Weaver diversity index) and expected heterozygosity (H) for isozyme/hordein loci revealed non significant associations except with respect to agro-ecological zones. In general, it was detected that sites in highland areas in central and northern regions may be more desirable for in situ conservation than sites in peripheral regions in terms of isozyme/hordein diversity and current rate of varietal replacement.     

水稻地方品种群体内的遗传多样性分析

【目的】研究水稻地方品种群体内的遗传多样性,为水稻地方品种的有效保护和利用提供理论依据。【方法】以来自云南省不同地区的齐头谷、大白糯、香谷、九月糯、接骨糯、冷水谷、黄版所、麻线谷等8个水稻地方品种为试验材料,分析7个主要农艺性状在群体内的表型变异,利用11对SSR引物进行水稻地方品种群体内的遗传多样性分析。【结果】在7个主要农艺性状中,穗抽出度、有效穗数和穗粒数在地方品种群体内的变异系数较大,分别为37.5%～950.1%,32.0%～49.4%和17.8%～37.5%,而剑叶宽和株高在地方品种群体内的变异系数较小,分别为8.2%～13.7%和4.5%～14.3%。8个水稻地方品种各群体内等位基因数的变幅为27～55个,每个位点的平均等位基因数为2.45～5.00个;稀有等位基因(基因频率小于5%)比率除麻线谷较小(26.0%)外,其余地方品种均较大,为43.2%～69.0%;平均Nei基因多样性指数变异在0.108 3～0.534 2,平均为0.281 3,在各地方品种间表现出极显著差异。AMOVA分析表明,地方品种群体间的变异率为65.9%,而群体内的变异率为34.1%;11对SSR引物中,RM333、RM257和RM180在各群体内既表现出较多的等位基因数(Na),分别为7.50,5.63和4.50个;又表现出较高的Nei基因多样性指数(He),分别为0.503 6,0.413 9和0.350 3。【结论】穗抽出度、有效穗数和穗粒数在地方品种群体内的表型多样性较高,而剑叶宽和株高在地方品种群体内的表型多样性较低。水稻地方品种群体内具有较高的遗传多样性,且在地方品种间表现出显著差异;AMOVA对水稻地方品种群体的遗传变异分析表明,有1/3的差异来源于群体内;RM333、RM257、RM180适合用于云南水稻地方品种群体内的遗传多样性检测。     

中国小麦地方品种籽粒强休眠特性的主效基因鉴定

前人研究表明,我国一些小麦地方品种籽粒休眠性强,穗发芽抗性好,可能受1～2对主效基因控制.本文利用小麦(Triticum aestivum)2个重组自交系群体(RILs,万县白麦子/京411,万县白麦子/中优9507)进行2点4年的田间试验,以期发掘控制我国小麦地方品种(万县白麦子)籽粒休眠的主效QTL位点.通过复合区间作图进行分析,分别在3AS和3BL染色体上鉴定出2个主效QTL,前者分布在Xbarc57和Xbarc294标记区间(在2个RILs群体中遗传距离分别为5.8和8.5 cM),在多年多点的实验中可解释25.6%～48.3%的表型变异;后者分布在Vp1和Xwmc446标记区间,在万县白麦子/中优9507群体中的遗传距离为8.1 cM,可解释23.5%～37.8%的表型变异.上述研究表明,我国小麦地方品种万县白麦子籽粒强休眠特性主要受Osd.ahau-3A、Qsd.ahau-3B这两个主效基因控制,在不同环境中表现出较好的遗传稳定性.可通过聚合育种的方法获得籽粒休眠性强、穗发芽抗性好的小麦新品种.     

Screening of barley landraces by direct selection for crop improvement

Abstract

Barley (Hordeum vulgare L.) landraces display a high degree of variability in morphological and developmental traits, in disease resistance, and in protein content. Representatives of 29 barley landraces from southeast Turkey were collected from farmers’ fields, for a total of 800 accessions. The objectives of this study were to characterize these accessions over four years for morphological and agronomical traits to be used for future selection and breeding program. The observed variation between landraces was very large for all traits. In the first year of testing the accessions showed average grain yields ranging from 197–2225 kg ha^?1. After three years of selection, promising accessions were tested at two different geographical regions and using two different irrigation methods. One line was identified which significantly out-yielded the local landrace in all of the testing years and had a higher average yield than the check genotypes.     

STUDY ON THE EFFECTS OF NITROGEN DEFICIENCY ON GRAIN IRON AND ZINC CONCENTRATIONS OF LANDRACE AND BRED WHEAT VARIETIES IN CHINA

It has been reported that nitrogen (N) deficiency can significantly reduce grain iron (Fe) and zinc (Zn) concentrations in wheat. Here, we investigated the grain Fe (GFeC) and Zn (GZnC) concentrations of 42 Chinese wheat varieties grown in a field trial under low and high N conditions. Analysis of variance revealed that both GFeC and GZnC significantly differed among varieties and between N treatments, and significant interactions existed between variety and N treatment. The GFeC under the low N condition was 94.8% of that under high N condition, ranging from 79.4% to 112.7%; the GZnC under low N condition was 74.8% of that under high N condition, ranging from 59.5% to 102.5%. Wheat varieties with high GFeC and GZnC under both N conditions were identified, and this kind of varieties is desirable in breeding wheat with enriched Zn and Fe under a range of soil N conditions.     

湖北省糯稻地方品种SSR遗传多样性研究

为评价湖北糯稻地方品种的遗传多样性,利用36对SSR标记对50份湖北地方糯稻品种进行PCR扩增和遗传多样性分析。结果表明,湖北糯稻地方品种的平均遗传多样性指数为0.710 7,多态信息含量平均为0.686 1,多样性较高。SSR标记聚类分析表明,湖北糯稻地方品种中遗传资源丰富,特别是籼粳糯稻成分互渗的品种,可广泛用于糯稻育种。     

山西小麦地方品种幼苗期抗旱性的鉴定

小麦幼苗长至二叶一心时,以200 g/L PEG-6000胁迫处理72 h,测定幼苗最大根长、根冠比、叶片相对含水量、相对电导率、SOD和POD活性以及MDA含量;采用模糊隶属函数与抗旱系数相结合的方法对各品种苗期的抗旱性进行综合分析;利用灰色关联度分析各个形态、生理指标与抗旱性的关系.结果表明:1)PEG胁迫下,9个小麦品种的最大根长、根冠比、相对电导率、SOD和POD活性及MDA含量均比对照高,而叶片相对含水量较对照低,而且差异均达到显著或极显著水平.2)利用隶属函数和抗旱系数相结合的方法对品种苗期抗旱性进行综合分析,各品种苗期的抗旱性表现依次为:白和尚头＞晋麦47＞竹杆青＞小红麦＞四月黄＞红皮冬麦＞灯笼红＞中麦9号＞忻县冬麦.3)SOD活性与苗期抗旱性关联度最大,其次为最大根长.     

Genotype analysis of the wheat semidwarf Rht‐B1b and Rht‐D1b ancestral lineage

In wheat, semidwarfism resulting from reduced height (Rht)‐B1b and Rht‐D1b was integral to the ‘green revolution’. The principal donors of these alleles are ‘Norin 10’, ‘Seu Seun 27’ and ‘Suwon 92’ that, according to historical records, inherited semidwarfism from the Japanese landrace ‘Daruma’. The objective of this study was to examine the origins of Rht‐B1b and Rht‐D1b by growing multiple seed bank sources of cultivars comprising the historical pedigrees of the principal donor lines and scoring Rht‐1 genotype and plant height. This revealed that ‘Norin 10’ and ‘Suwon 92’ sources contained Rht‐B1b and Rht‐D1b, but the ‘Seu Seun 27’ source did not contain a semidwarf allele. Neither Rht‐B1b nor Rht‐D1b could be definitively traced back to ‘Daruma’, and both ‘Daruma’ sources contained only Rht‐B1b. However, ‘Daruma’ remains the most likely donor of Rht‐B1b and Rht‐D1b. We suggest that the disparity between historical pedigrees and Rht‐1 genotypes occurs because the genetic make‐up of seed bank sources differs from that of the cultivars actually used in the pedigrees. Some evidence also suggests that an alternative Rht‐D1b donor may exist.