Genetic dissection of endosperm hydration in malting barley (Hordeum vulgare)

Hydration of the endosperm is a critical part of the malting process that ensures proper modification of the grain. However, little is known about the genetic controls of endosperm hydration and its relationship to agronomic and malt quality traits. The extent of endosperm hydration is estimated through hydration index (HYI). We measured HYI, agronomic, and malt quality traits on a 169-line subset of the NSGC Barley Core Panel, which includes global malt lines, some dating from the inception of European breeding programmes. Utilizing GWAS, 61 QTLs were identified for HYI, dormancy, agronomic, and malt quality traits. Of these, six were found to be related to HYI and were located on 1H, 2H, 3H, 6H, and 7H. We found HYI QTLs cosegregating with kernel size and hardness (1H and 3H), malting quality (2H and 6H), and dormancy (2H and 6H). These results indicate that endosperm hydration after steeping can be improved by selecting high HYI alleles on 2H, 6H, and 7H, positively impacting malting quality without negatively impacting kernel size or dormancy.     

Identification of novel alleles from wild barley for the improvement of alpha‐amylase and related malt quality traits

Germplasms consisting of 64 wild barley accessions (Hordeum vulgare ssp. spontaneum) were examined for polymorphisms in α‐amylase using both isoelectric focusing (IEF) and thermostability assays. Wide variation was found for the high pI α‐amylase with 20 IEF band patterns identified. Enzyme activity and thermostability assays showed large differences among α‐amylase isoenzymes. Two wild accessions Tel‐Shoket CPI 77146‐32 and Afiq CPI 77128‐41 showed superior enzyme activity and thermostability compared with commercial varieties such as ‘Baudin’, ‘Flagship’ or ‘Navigator’. The functionality of the Tel‐Shoket allele was validated in backcross lines with ‘Flagship’ as the recurrent parent. The Tel‐Shoket allele at the amy1 locus increased α‐amylase thermostability at 75°C by 8.4% and α‐amylase activity in kilned malt by 18.7%. The introgression of the wild allele also led to significant improvements in fermentability, hot water extract and viscosity. Gene sequencing showed that there are three single nucleotide polymorphisms in the Tel‐Shoket amy1 sequence, which can be used as diagnostic markers for the selection of this allele in breeding programmes.     

水稻胚胎和胚乳双缺陷突变体eed1的表型与遗传分析

从由化学诱变剂甲基磺酸乙酯(ethylmethane sulfonate,EMS)处理的粳稻品种中花11突变体库中,筛选到一个可稳定遗传的胚胎和胚乳发育缺陷的突变体,命名为embryo and endosperm defective 1 (eed1)。eed1籽粒千粒重、颖果的粒长、粒宽、粒厚、萌发率、总淀粉、直链淀粉和贮藏蛋白系列指标较野生型均显著降低。eed1颖果严重皱缩,且胚乳呈粉质。利用扫描电镜观察发现,与中花11相比, eed1胚乳中淀粉粒排列疏松,多以单一、分散的淀粉粒存在,且呈近似球形。eed1胚胎结构异常,部分颖果未见有胚胎分化的痕迹。qRT-PCR发现, eed1胚乳中参与淀粉和贮藏蛋白合成的大部分基因表达下调。利用eed1与籼稻南京6号杂交得到的F2分离群体进行基因定位分析,将EED1定位于9号染色体长臂672kb的范围内,包含114个开放读码框。本研究为进一步解析EED1基因调控水稻胚胎和胚乳发育的机制奠定了基础。     

啤酒大麦精化力及其有关酿造品质性状的胚和胚乳遗传效应分析

以7个二棱大麦品种及其半双列杂交F_2种子的两年资料,采用包括基因型×环境互作的麦芽品质性状遗传模型,对糖化力(DP)、α-淀粉酶活力(αAA)、β-淀粉酶活力(βAA)和麦芽N含量的胚和胚乳直接遗传效应及其环境互作进行了遗传研究。结果表明,这4个麦芽品质性状既受基因型影响又受环境(年份)影响。DP和βAA的遗传主要受胚乳直接显性效应和胚显性×环境互作效应的控制,胚加性效应×环境互作以及胚乳加性效应×环境互作对其表现有一定的影响。αAA和麦芽N的遗传同时受胚和胚乳遗传效应的决定,但以胚直接显性效应和胚乳直接加性效应为主,并发现胚加性和显性与环境以及胚乳加性与环境均有显著的互作存在。DP与βAA有显著正相关(rc=0.5601)。麦芽N与DP的正相关主要在于二者都与βAA有密切关系。αAA和麦芽N含量的普通狭义遗传率分别为26.1％和27.8％。     

啤酒大麦糖化力及其有关酿造品质性状的胚和胚乳遗传效应分析

以7个二棱大麦品种及其半双列杂交F2种子的两年资料,采用包括基因型X环境互作的麦芽品质性状遗传模型,对糖化力(DP),α-淀粉酶活力(αAA),β-淀粉酶活力甲(βAA)和麦芽N含量的胚和胚乳直接遗传效应及其环境互作进行了遗传研究。结果表明,这4个麦芽品质性状既受基因型影响又受环境(年份)影响。DP和βAA的遗传主要受胚乳直接     

Analysis of embryo, endosperm, cytoplasmic and maternal effects for heterosis of protein and lysine content in indica hybrid rice

The heterosis controlled by genetic main effects and genotype × environment (GE) interaction effects for protein content and lysine content traits of indica hybrid rice, Oryza sativa L., was studied by using a genetic model for quantitative traits of triploid endosperm. The experiment was conducted over 2 years in a factorial design that included nine cytoplasmic male-sterile lines as females and five restorer lines as males. It was revealed that heterosis of protein content and lysine content were simultaneously controlled by genetic main effects and GE interaction effects. Maternal general heterosis and maternal interaction heterosis were observed. Embryo heterosis or cytoplasm heterosis for lysine content and endosperm heterosis for protein content were more important in general heterosis. Embryo interaction heterosis and cytoplasm interaction heterosis were more important for protein content, but endosperm heterosis was only important for lysine content in GE interaction heterosis. It was shown that some indica hybrid crosses had significant positive heterosis for protein content. Negative heterosis for lysine content was observed in most hybrid crosses.     

Correlated effects of exotic pollen‐fertility restorer genes on agronomic and quality traits of hybrid rye

In CMS (cytoplasmic male sterility)‐based hybrid rye (Secale cereale L.) breeding, effective pollen‐fertility restoration is an essential prerequisite for achieving maximum grain yield on the one hand and for minimizing ergot (Claviceps purpurea) infestation on the other. Restorer genes for the CMS‐inducing ‘Pampa’ cytoplasm derived from landraces collected in Iran and Argentina are used by breeders for achieving this goal. Here, restorer genes from four germplasm sources (‘Altevogt 14160’, ‘IRAN III’, ‘Trenelense’ and ‘Pico Gentario’) were analysed by producing three‐way cross hybrids between an elite CMS single cross and pollinators with and without a given restorer gene. Materials were evaluated on large drilled plots for restorer index (RI), grain yield, plant height and other traits in six environments. In experiment 1, a restorer gene from ‘Altevogt 14160’ was used. Seven pairs of marker‐selected carrier and non‐carrier backcross lines served as pollinators. In experiment 2, the pollinators were 17 backcross line pairs from the other three germplasm sources. These lines were grouped as high (RI > 67%) and low restorers (RI < 30%), respectively, using testcrosses with a highly diagnostic CMS tester. Hybrids carrying an exotic restorer gene suffered from a significant grain yield reduction by 4.4% and 9.4% and were 9.3 and 4.8 cm taller in experiments 1 and 2, respectively. Thousand‐kernel weight was reduced, whereas quality traits were only slightly affected. For all traits, significant genetic variance existed among the testcrosses to the presence vs. absence of a given exotic restorer gene. This offers a chance for the breeder to reduce or ultimately overcome the presently observed performance reductions brought about by exotic restorer genes.