The Grain Quality of Landraces of Wheat as Compared with Modern Cultivars

Landraces of tetraploid and hexaploid wheat from the Northern Negev in Israel were evaluated over two years for their grain quality attributes. Twenty-one populations of tetraploid wheat (Triticum durum, represented by 56 accessions) and 8 populations of hexaploid wheat (T. aestivum and T. compactum, represented by 13 accessions) were compared with 3 and 4 modern improved Israeli cultivars of tetraploid and hexaploid reheat, respectively. This comparison allowed to estimate the progress made in the improvement of gram quality m present-day cultivars. Except for grain protein content in the hexaploids, significant variation was revealed among landraces in kernel weight, protein content (tetraploids), sedimentation, mixograph score and carotin content. The best modern cultivars were comparable to the best landraces in kernel weight and carotin content (tetraploids), indicating that modern wheat breeding maximized kernel weight and carotin content, as compared with the tested landraces. Gram protein content and/or quality was not maximized in modern cultivars and its improvement was deemed possible by introgression from the best landraces in this respect.     

密穗小麦(Triticum compactum)农艺性状分析

对来自19个国家的60份密穗小麦(Triticum compactum)材料进行农艺性状分析。结果表明,密穗小麦抽穗期从151~195 d,包括了早熟到晚熟的各种类型,多表现为晚熟。植株高度总体偏高,少数适中。单株有效分蘖数大多在10个以上,有效穗数变幅为6.8~30.2个,成穗率平均为70%。穗长、小穗数和单位长度着生小穗数存在一定差异,但均表现为密穗型。大部分材料穗粒数较多,但千粒重明显偏低。多数材料严重感染白粉病,仅有8份材料抗白粉病。性状相关分析表明,随着抽穗期缩短,穗粒数和千粒重增加,但小穗数有减少的趋势。     

我国半知菌四新记录属

本文首次记载了四种腐生于木头和枯枝,分别代表我国半知菌新记录属的真菌。采自柳树(Salix sp.)和白榆(Ulmus pumila)的掌状网格孢(Dictyosporium toruloides)其产孢细胞为全壁芽生式,分生孢子手掌状;粘环孢(Myxocyclus polycistis)采自桦属(Betula)和栒子属(Cotoneaster)植物,是该菌的寄主世界新记录,这种菌产生盘状至垫状的子实体,产孢细胞为全壁芽生式,分生孢子砖格状,具离壁隔膜,孢子及梗包裹在胶质壳内;忍冬锥壳孢(Sphaerographium lonicerae)其分生孢子器具长喙,生于忍冬(Lonicera heterophylla)枝上,产孢细胞为内壁瓶梗状芽生式,分生孢子镰刀状;生于白榆枝条上的门座孢(Thyrostroma compactum)具垫状分生孢子座,全壁环痕芽生式产孢细胞及暗色的砖格分生孢子。     

不同品质类型小麦戊聚糖含量及其与品质的关系

为给小麦品质的遗传改良提供依据,选用不同品质类型的7个小麦推广品种和1个密穗小麦,研究了戊聚糖含量及其与品质的关系.结果发现,中强筋小麦品种具有比弱筋小麦品种更高的戊聚糖含量,且不同筋力的推广品种戊聚糖含量表现出较大差异.弱筋小麦的水溶性戊聚糖含量与延展性、饼干直径呈极显著和显著负相关;非水溶性戊聚糖、总戊聚糖与饼干直径亦呈极显著负相关;与吹泡示功仪参数、RVA参数也具有较为丰富的相关性.本研究进一步证实宁麦9号和扬麦13具有良好的饼干品质.密穗小麦具有较低的戊聚糖含量,同时其饼干直径、厚度、直径/厚度均与弱筋小麦品种相近,可能是一个优良的弱筋、低戊聚糖含量的饼干小麦资源.     

Effect of variation at Glu-D1 on club wheat end-use quality

Club wheats (Triticum aestivum L.), having the allele at the C locus conferring short spike rachis internodes and giving compact appearance of spikes, which have unique and highly desirable soft white wheat end-use quality characteristics are a vital submarket class of soft white wheat in the US Pacific Northwest. Two important varieties, ‘Tyee’ and ‘Albit’, are heterogeneous for high molecular weight glutenin subunits 2 + 12 and 5 + 10 encoded by the Glu-D1 locus. Replicated near-isogenic lines (NILs) of club wheats ‘Tyee’ and ‘Albit’ were grown in four field environments and used to determine the effect of Glu-D1 coded high molecular weight glutenin subunits (HMWGS) 5 + 10 and 2 + 12 on various end-use quality traits. The greatest effect of variation at this locus was observed for mixing time to peak, where there was significant variation (P < 0.01) between each 5 + 10 and 2 + 12 NIL group in each environment. Mixing time values for the 2 + 12 NILs for both ‘Albit’ and ‘Tyee’ ranged from 0.60 to 1.23 min lower than the 5 + 10 NILs. Mean values for traits mixing time to peak, cake volume, and viscosity were more favourable for the 2 + 12 NIL groups for all genotypes in all environments. No effects of these HMWGS were detected for test weight, kernel hardness, whole wheat protein, flour yield, ash, flour protein or cookie diameter. Selection for HMWGS 2 + 12 in club wheat breeding programmes should have positive effects on end-use quality.     

密穗小麦(Triticum compactum Host.)醇溶蛋白遗传多样性分析

采用酸性聚丙烯酰胺凝胶电泳（A-PAGE）对来自美国、澳大利亚、巴基斯坦、意大利、土耳其等24个国家的70份密穗小麦材料进行了醇溶蛋白位点的遗传变异分析.结果表明,70份供试材料出现了69种醇溶蛋白带型.共电泳分离出54条谱带,其中每份材料可分离出14～29条带,平均22条.谱带在α、β、γ、ω四个区都存在较大的差异,分别有36、27、37和63种变异类型,表明密穗小麦醇溶蛋白位点具有较丰富的遗传多样性.聚类分析发现,多数材料的遗传聚类关系与其来源地有一定相关性.     

海南岛爪哇白豆蔻青枯病病原菌的进一步鉴定

爪哇白豆蔻青枯病是近年来在我国首次发现的一种新病害。通过对病害的诊断和病原菌的形态、染色反应、培养性状、生理生化特性以及致病性的进一步测定,确认本病的病原菌是青枯假单胞菌[Pseudomonas solanacearum(Smith)Smith]。根据本病菌的供试菌株对6种糖、醇的利用情况,认为本病菌株属于Hayward的生物型Ⅲ。     

密穗小麦(Triticum compactum Host.)α-醇溶蛋白基因5’上游调控区序列分析

本文根据已报道的α-醇溶蛋白基因5’上游调控区和编码区的保守序列,设计特异性引物,以5份密穗小麦DNA为模板,用PCR克隆的方法获得了51条α-醇溶蛋白基因5’上游调控区序列。对长度大于380 bp的19条序列进行了分析,发现19条序列均含有与基因表达相关的重要调控元件,包括胚乳基序元件TGTAAAG、GCN4类似元件ATGAGTCAT、CAAT框、AAA G基序、TA-TA框、GCN4类似基序ATGAC(T)GATCAT以及CAC-box,同时在序列中出现了AACA元件。序列比对表明,密穗小麦与普通小麦和乌拉尔图小麦α-醇溶蛋白5’上游调控区存在较为丰富的变异,遗传差异较大。对各序列的5’上游调控区进行聚类分析,结果发现基于调控区序列不能完全区分材料的种属,同时根据已知染色体位置的序列,可以看出上游调控区序列并未表现出染色体特异性。     

密穗小麦(Triticum compactum)Glu-1位点亚基组成分析

采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)对来自21个国家的50份密穗小麦Glu-1位点亚基组成进行了鉴定与分析.结果表明,在3个位点共检测到15种不同的亚基类型,21种组合形式.其中,以2*,7 8,2 12和N,7 8,2 12组合为主,各占22%和16%.在各位点等位变异中,Glu-B1位点变异类型最多,共10种,以7 8(42%)、20(20%)和21(12%)为主.Glu-A1和Glu-D1位点各有3种和2种等位变异,分别以N(50%)和2 12(88%)为优势亚基.更为重要的是选出一些具有优质亚基的材料,其中1份材料亚基组合为(1、7 8、5 10),品质评分达到满分(10分)可供小麦遗传改良.     

Variation at Glu-1 Loci in Club Wheats

Hexaploid club wheats (Triticum aestivum L.) possess unique end-use quality characteristics and are grouped as a U.S. market subclass of soft white common wheat. Although there have been many reports on associations among high-molecular-weight glutenin storage protein (HMW-Glu) sub-units with end-use quality in hard wheats; there has been very limited work done on surveying the club wheats for these subunits. The HMW-Glu subunits, spike types and grain color were determined for 41 U.S. club wheat cultivars and 79 club accessions obtained from the National Small Grains Collection (NSGC), USDA-ARS. Accession ‘Harlan JR 35’ (PI 420948), which appears morphologically to be a hexaploid club wheat, was determined to be tetraploid. Egyptian line ‘Maya II-Tel's’ (PI 422288) was shown to have previously undescribed HMW-Glu subunits. In the U.S. club wheats the most common HMW-Glu subunits were: null, 49 % (Glu-A1); 6, 37 % (Glu-B1); and 2 + 12, 94 % (Glu-D1). In the NSGC group the most common HMW-Glu sub-units were: 2*, 52 % (Glu-A1); 7 + 8, 31 % (Glu-B1); and 2 + 12, 92 % (Glu-D1). The high frequency of subunits 2 + 12 in the club wheat groups has not been observed previously in numerous surveys of diverse wheat cultivars. The Glu-B1 subunits 6 (without subunit 8) and 20 which have not been reported in US red wheats, were shown to be common in both club wheat groups. A comparison of diversity indices, including previous studies on HMW-Glu subunit frequencies on all market classes of wheat, showed that the club groups are as diverse for the Glu-A1 and Glu-B1 loci and less diverse for the Glu-D1 locus.