Genetic effects and genotype × environment interactions for cooking quality traits in Indica-japonica crosses of rice (Oryza sativa L.)

Indica-japonica hybridization is an important approach for developing superior performing hybrids in rice (Oryza sativa L.). In view of the scanty information available on cooking quality characters in indica-japonica crosses, an investigation was undertaken to estimate genetic and genotype × environment variance and covariance components of amylose content, gel consistency and alkali digestion value, and to determine the relative importance of direct genetic effects, maternal genetic effects and cytoplasmic effects in the genetic variations of the three quality characters. Two indica photo-sensitive genic male sterile (PGMS) lines and four japonica varieties were used as parents to make crosses. Genetic model with genotype × environment interactions for triploid endosperm was used for genetic studies of the three cooking quality characters. Variance component analysis revealed that genetic variations of the three characters were mainly attributable to direct additive and maternal additive effects, and the three traits had significant direct and maternal heritabilities. Genotype × environment interactions were mainly dominance × environment (including direct dominance × environment and maternal dominance × environment) and cytoplasm × environment interactions. Environment factors could only affect the expression extent of dominant genes, without changing their directions. Predicted values of genetic effects indicated that the parental lines, ‘VI-70’ and ‘H9304-1’, appeared to be best for amylose content, ‘T 1950’ and ‘Suxuan’ appeared to be best for gel consistency and alkali digestion value. This revised version was published online in August 2006 with corrections to the Cover Date.     

不同环境下杂交粳稻直链淀粉含量的遗传分析

以粳稻三系材料组配的5×5不完全双列杂交亲本及F₂、F₃种子为试材, 应用包括胚乳效应、细胞质效应、母体效应的三倍体种子性状遗传模型, 对不同年份、不同穗位两种环境设计下的直链淀粉含量进行遗传分析。结果表明, 两种环境下, 直链淀粉含量的方差组成均以基因型方差为主。遗传主效应方差以胚乳加性方差为主。以穗位作为环境因子时, 能检测到显著的细胞质方差, 互作方差以直接显性×环境互作方差为主, 其次是细胞质×环境互作方差, 但对互作效应值的遗传预测表明, 绝大部分品种所有粒位均以细胞质×环境的互作效应值最大, 且细胞质×环境互作使不育系强、中势籽粒的直链淀粉含量降低、弱势粒直链淀粉含量提高, 恢复系则相反, 强、中势籽粒直链淀粉含量提高, 弱势粒直链淀粉含量降低。以年份作为环境因子时, 细胞质方差不显著, 互作方差以母体显性×环境互作方差为主。     

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     

Genetic impacts of fiber sugar content on fiber characters in Sea Island cotton, Gossypium barbadense L.

A genetic model with additive effect, dominant effect, additive × additive effect, and their interaction with environment effect (GE) was employed to analyze the 2-year data of F₁ and F₂ hybrids from 5 × 4 diallel cross, whose parents were Sea Island cotton with different fruit branch types. Unconditional and conditional genetic variances were analyzed to demonstrate genetic impacts of fiber sugar content on fiber characters. Results of unconditional genetic variances showed that dominance × environment interaction effect and additive × additive epistatic effects mainly controlled the genetic variation of fiber sugar content, and environment influenced the inheritance of fiber sugar content. Fiber uniformity, fiber elongation, and fiber micronaire were mainly controlled by dominance × environment effects. Fiber strength was mainly controlled by the interaction of additive × additive epistatic effects and the environment. Analysis of correlation coefficients indicated that the varieties or hybrids with high-fiber sugar content had short fiber, low-fiber uniformity, strength, and fineness, which indicated the close co-variation between fiber quality traits and fiber sugar content. Relatively better fiber quality traits could be obtained effectively through selecting parents with low-fiber sugar. Fiber sugar content of different parents had different genetic effect on fiber quality traits.     

大豆籽粒异黄酮含量的遗传效应研究

大豆异黄酮含量差异较大的6个大豆品种为亲本，通过双列杂交配置杂交组合，测定了两个环境条件下亲本、F₁和F₂种子的异黄酮含量。采用双子叶植物种子数量性状遗传模型和统计分析方法, 分析了胚、细胞质和母体植株等不同遗传体系的基因效应以及环境互作效应。结果发现大豆籽粒异黄酮含量的表现主要受制于母体遗传效应, 其次为胚(子叶)基因效应,细胞质效应影响较小。不同遗传体系的基因主效应明显大于环境互作效应。异黄酮含量的机误方差较大,说明异黄酮含量更易受到环境条件变化影响。亲本遗传效应分析表明, 选用豫豆29或郑90007亲本有利于增加杂种后代大豆籽粒异黄酮含量,提高品质改良的效果。胚显性方差和母体显性方差均极显著，表明种子杂种优势和母体杂种优势会同时存在，而且是不受环境影响的主效应基因。     

Analysis of the genetic control of β-carotene and <Emphasis Type="SmallCaps">l</Emphasis>-ascorbic acid accumulation in an orange-brownish wild cherry tomato accession

An additive-dominance, additive × additive (ADAA) and genotype × environment interaction mix model was used to study the genetic control of β-carotene and l-ascorbic acid in six basic generations (P₁, P₂, F₁, F₂, BC₁P₁ and BC₁P₂) of tomato derived from the cross CDP8779 accession (Solanum lycopersicum L.) × CDP4777 accession (S. lycopersicum var. cerasiforme). The study was performed in two environments: (1) open field; (2) protected environment, consisting of hydroponic cultivation in a glasshouse. The results indicate that β-carotene accumulation was mainly additive (32.2% of the genetic component), with a small dominant component (4.2%) and an important additive × environment interaction contribution (63.6%). In target environments with moderate to high temperatures and no limiting radiation, this the expression additive × environment interaction could substantially enhance the β-carotene content. This trait showed also a high narrow-sense heritability (h ² = 0.62). Ascorbic acid accumulation was also mainly additive (61.7% of the genetic component), with a minor additive epistatic component (21.5%). This epistatic effect caused a negative heterosis that reduced the positive main additive effect. Nevertheless, in the described target environments, the additive × environment interaction contribution (16.8%) may enhance the ascorbic acid content and compensate for the negative heterosis effect. The total narrow-sense heritability of this trait can be considered useful (h ² = 0.52). In conclusion, the CDP4777 accession is a very interesting donor parent for the joint improvement of β-carotene (without diminishing lycopene content) and ascorbic acid content in commercial nutraceutical tomato breeding programmes; the F₁ hybrids derived from this accession showed nearly 450% of the commonly reported average β-carotene content and close to 130% of the ascorbic acid content of the female parent.     

Genotype-environment interaction of barley doubled haploids with regard to malting quality

The genotype-environment (GE) interaction of barley doubled haploid (DH) lines was studied in relation to some malting quality characters. DH lines were obtained, using the bulbosum method, from F₁ hybrids between the cultivars ‘Grit’ and ‘Havila’. Thirty DH lines, the parental forms, F₂ and F₃ hybrids of ‘Grit’בHavila’ and the standard cultivar ‘Rudzik’ were studied in a series of field experiments repeated at six environments. Malt protein content, Kolbach index, extract yield and malt fine-coarse difference were measured. The statistical analysis was performed using the computer program SERGEN. For protein content, it was found that most of the lines studied were stable, i.e. their GE interactions were not significant. Among the malt traits, phenotypic values of Kolbach index and fine-coarse difference were most dependent on environmental conditions. For Kolbach index, only one line was found to be stable, while for fine-coarse difference, all lines displayed interaction with the environment.     

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.     

不同环境条件下稻米组氨酸和精氨酸的胚乳和母体植株QTL分析

利用汕优63重组自交系与双亲回交产生的BC1F1和BC2F1群体,采用新发展的包括环境互作效应在内的多遗传体系QTL作图方法和基因定位软件,对稻米两种半必需氨基酸（组氨酸和精氨酸）进行三倍体胚乳和二倍体母体植株等不同遗传体系的QTL定位分析。共检测到10个控制组氨酸含量的QTL以及8个控制精氨酸含量的QTL。全部QTL均具有极显著的三倍体胚乳和二倍体母体植株基因的加性主效应,其中4个QTL具有显著或极显著的三倍体胚乳显性主效应,7个QTL还具有明显的环境互作效应。     

Heritabilities and Minimum Gene Number Estimates of Carrot Carotenoids

Summary Broad sense heritabilities and gene numbers were estimated for the production of total carotenoids and the major component carotenoids of carrot storage roots: phytoene, ζ-carotene, β-carotene, α-carotene, and lycopene. Two crosses with different backgrounds were evaluated: orange B493 × white QAL and orange Brasilia × dark orange HCM. The HCM (high carotene mass selection), Brasilia and B493 parents had both α-carotene and β-carotene, but HCM had proportionally more α-carotene. Carotene content in F ₂ populations ranged from 522 ppm to 1714 ppm in Brasilia × HCM and from 0 to 695 ppm in B493 × QAL progeny. F ₂ plants segregating for absence of α-carotene were identified in B493 × QAL. Broad-sense heritabilities ranged from 28% to 48% for all carotenes except lycopene and phytoene where estimates were 44% to 89% in the Brasilia × HCM cross, All heritability values exceeded 88% for the B493 × QAL cross, except one estimate for lycopene. The estimated number of genes was 4 conditioning α-carotene, 2 to 3 each for β-carotene and total carotenes and one each for ζ-carotene, lycopene and phytoene in the orange × dark orange cross. In the orange × white cross, the estimates were 4 genes for α-carotene, 1 to 2 each for lycopene and total carotenes and 1 for each of the other carotenes. These results are in general agreement with QTL studies and they provided evidence for continuous inheritance of α-carotene, β-carotene and total carotenoids in the orange × dark orange cross and discrete inheritance for β-carotene and total carotenoids in the orange × white cross.Part of thesis “Biometrical studies and quantitative trait loci associated with major products of the carotenoids pathway of carrot (Daucus carota L.)” presented by the first author as partial fulfillment of the requirement of the PhD degree in Plant Breeding and Plant Genetics, UW-Madison, USA, 2001.     

普通玉米主要营养品质性状的遗传效应分析

用13个普通玉米自交系按NCⅡ设计（7×6）研究了普通玉米主要营养品质性状的遗传效应。结果表明，普通玉米主要营养品质性状的遗传受种子二倍体胚、三倍体胚乳、细胞质和二倍体母体植株4套遗传体系的控制；主要品质性状4套遗传体系的效应值之间无太大的差异，蛋白质、淀粉和赖氨酸含量的胚遗传效应全部体现为胚加性遗传效应，而4种品质性状的胚乳遗传效应则全部由胚乳显性遗传效应构成；母体遗传效应主要表现为母体加性效应；遗传效应预测值表明亲本9636、99S2041-1-1-1和478在普通玉米品质改良中可能有一定的应用潜力。结果还发现，不同品质性状间存在不同程度的遗传相关，因此对这些性状进行间接选择或杂种优势利用均可取得一定的效果。     

Inheritance of β-carotene concentration in durum wheat (Triticum turgidum L. ssp. durum)

Despite being one of the important characteristics in determining pasta quality in durum wheat (Triticum turgidum ssp. durum), there is no direct report on inheritance of β-carotene concentration. The objectives of this study were to determine the inheritance of β-carotene concentration and the number of genes involved in six crosses of durum. For the cross PDW-233 (P₁) × Bhalegaon-4 (P₂), F₁, F₂, BCP₁ and BCP₂ populations were developed. For all other crosses, only the F₁ and F₂ populations were developed. β-carotene concentration was determined for all populations and parents of each cross grown at Hol, Maharastra, India. The cross PDW-233 × Bhalegaon-4 was also evaluated at Dharwad, Karnataka, India. Low β-carotene concentration was partially dominant in most of the crosses. Broad sense heritability was 67 and 91% at Dharwad and Hol, respectively, for the cross PDW-233 × Bhalegaon-4 and varied from 74 to 93% for the other five crosses indicating the presence of additive gene effects. The frequency distributions of the trait in the F₂ populations were not normal and were skewed towards the lower parent. Segregation of β-carotene concentration in the six F₂ populations indicated that at least two major genes and two or three minor genes with modifying effects govern the trait. Analysis of variance indicated that environment had comparatively little influence on the trait and this should allow for easy selection. The joint scaling test revealed additive × additive, additive × dominance and dominance × dominance epistatic interactions in the cross PDW-233 × Bhalegaon-4. These authors contributed equally.     

A simple and efficient cryopreservation of in vitro-grown shoot tips of `Troyer' citrange [Poncirus trifoliata (L.) Raf. × Citrus sinensis (L.) Osbeck.] by encapsulation-vitrification

Wheat of two strong high-protein and two weak low-protein cultivars from New Zealand and Australia were milled to commercial specifications. All millstreams were tested for α-amylase, β-amylase, falling number, protein, starch, damaged starch, amylose, amylopectin, pentosan and ash. The distribution of β-amylase in millstream flours was more variable among cultivars than α-amylase. Generally, both enzymes had lowest activity in sizing and early reduction flours. α-Amylase was very high in the bran, pollard and germ fractions, in which ash content was very high, whereas β-amylase was low in these fractions. These observations, together with the moderate correlation of α-amylase and poor correlation of β-amylase to ash content, suggest that most α-amylasein flour derives from contamination with bran, pollard and germ, whereas most β-amylase derives from the endosperm. Falling numbers varied between the cultivars, but variation amongst millstreams for each cultivar was low, except for cv. Frame, which had particularly high falling number values (834 and 1197) in second and third break flours. These two flours had some of the highest α-amylase levels and lowest starch levels. However, they also had very high protein content (22 and 26%) and very low starch damage (3.2 and 4.5%), which may contribute to the high falling numbers. When endogenous α-amylase in the flour with the highest falling number was supplemented with high levels of barleyα-amylase, the flour withstood the detrimental effects of α-amylasein baking (sticky crumb, poor crumb texture and loaf volume) better than flours of lower falling number, but did not withstand the effects ofα-amylase on falling number. This revised version was published online in August 2006 with corrections to the Cover Date.     

大豆脂肪酸组分的胚、细胞质和母体遗传效应分析

利用5个大豆品种配制20个杂交组合,采用广义种子遗传模型分析了大豆脂肪酸组分的胚、细胞质和母体植株等3套遗传体系的基因主效应和基因型×环境效应。棕榈酸含量、硬脂酸含量和亚油酸含量是以基因型×环境互作效应为主。亚麻酸和油酸的遗传主效应和基因型×环境互作效应相近。在脂肪酸组分的遗传主效应中,棕榈酸、硬脂酸和亚油酸含量是以胚主效应为主。油酸含量和亚麻酸含量以细胞质主效应为主。在基因型×环境互作方差中,脂肪酸组分以极显著的胚互作方差为主。亚麻酸含量是以基因的加性效应和加性×环境互作效应为主,棕榈酸含量、硬脂酸含量、油酸含量和亚油酸含量以基因的显性和显性×环境互作效应为主。棕榈酸含量和油酸含量是以普通狭义遗传率为主。硬脂酸、亚油酸含量和亚麻酸含量以互作狭义遗传率为主。在普通狭义遗传率中,棕榈酸含量、油酸含量和亚麻酸含量以细胞质普通遗传率和母体普通遗传率为主。在互作狭义遗传率中,油酸含量和亚麻酸含量以胚互作狭义遗传率为主,亚油酸含量以母体植株互作遗传率为主。棕榈酸含量、硬脂酸含量、油酸含量和亚油酸含量以细胞质及母体选择响应和互作选择响应为主,亚麻酸含量的胚普通选择响应和互作选择响应为主。     

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.     

籼稻稻米直链淀粉含量的胚、胚乳、细胞质和母体遗传效应分析

采用禾谷类作物种子数量性状遗传模型和统计分析方法, 分析了籼稻稻米直链淀粉含量的 胚、 胚乳、 细胞质和母体植株遗传效应以及环境互作效应。 结果发现稻米直链淀粉含量 的表现主要受制于基因的遗传主效应, 环境互作效应对其影响较小。 控制直链淀粉含量的 遗传主效应以胚乳效应为主, 细胞质效应和母体效应对直链淀粉含     

Evaluation of methods for the assessment of malting quality in barley breeding

Summary Methods for assessing malting quality in barley breeding were evaluated for their precision, including variation between different batches, analysts and barley samples. The barley characters measured were grain moisture, ground grain moisture (two methods), grain weight, steep moisture, malt moisture (two methods), malt yield, malt nitrogen, malt soluble nitrogen, Kolbach index, malt diastatic power, malt -amylase, malt -glucanase, wort refractive index, hot water extract, extract yield, wort reducing sugars, wort total carbohydrates, wort -amino nitrogen and wort total nitrogen. The value of these measurements in barley breeding is discussed.     

Generation mean analysis of leaf chlorophyll concentration from mid-silking to physiological maturity in some tropical maize (Zea mays L.) genotypes under low and high nitrogen dosages

Genetic control of the leaf chlorophyll concentration (LCC) in tropical maize (Zea mays L.) genotypes has not been established, especially at different reproduction growth stages under low and high nitrogen (N). A generation mean analysis study was conducted to identify the genetic effects that govern the LCC from mid-silking to physiological maturity under high (120?kg?N?ha^?1) and low (60?kg?N?ha^?1) (N) regimes for two seasons in a randomized complete block design with two replications during main and offseason of year 2009 at Inyala Agricultural Training Institute in Mbeya, Tanzania. This study revealed that mid-parent heterosis for the LCC increased with growth stages under both N dosages but it was more pronounced under low N dosage. Generally, genetic effects for LCC were more easily estimable under high than under low N dosage. Additive gene effects decreased with growth stage, whereas dominance effects increased, irrespective of the genotype and N regime. All genetic effects except dominance?×?dominance interaction were significant at some stages only in cross T20?×?N_G8. The ratio of fixable (additive plus additive?×?additive) to the non-fixable (dominance plus additive?×?dominance, and dominance?×?dominance) genetic effects was 74?C26?% under high N dosage, and 35?C65?% under the low N dosage for the T20?×?C58, while for the T20?×?N_G8, the ratio was 37?C63?% under high N dosage, and 20?C80?% under the low N dosage. The trend observed suggest that fixable effects are preponderant under the high N dosage in one cross, while non-fixable effects prevailed under the low N dosage in the other cross.     

Identification of QTL underlying the filling rate of protein at different developmental stages of soybean seed

Seed protein content at the harvest stage is the sum of protein accumulation during seed filling. The aim of our investigation was to identify loci underlying the filling rate of seed protein at different developmental stages. To this end, we used 143 recombinant inbred lines (RILs) derived from the cross of soybean cultivars ‘Charleston’ and ‘Dongnong 594’ and composite interval mapping with a mixed genetic model. The genotype × environment interactions of the quantitative trait loci (QTL) were also evaluated. Thirty-nine unconditional QTL underlying the filling rate of seed protein at five developmental stages were mapped onto 14 linkage groups. The proportion of phenotypic variation explained by these QTL ranged from 4.88 to 26.05%. Thirty-eight conditional QTL underlying the filling rate of seed protein were mapped onto 16 linkage groups. The proportion of phenotypic variation explained by these QTL ranged from 1.87 to 31.34%. The numbers and types of QTL and their genetic effects on the filling rate of seed protein were different at each developmental stage. A G × E interaction effect was observed for some QTL.     

Genetic analysis of low-temperature tolerance during germination in tomato, Lycopersicon esculentum Mill.

The genetic basis of low-temperature tolerance during germination of tomato seed was investigated using two approaches. First, a cold-tolerant (PI 120256) and a cold-sensitive tomato cultivar (UCT5) and their reciprocal F₂, F₃ and BC₁ progeny (total of 10 generations) were evaluated for germination at a low (11 ± 0.5°C) and a high (control) temperature 20 ±0.5° C) Weighted least-square regression analysis indicated that in the low-temperature treatment most of the variation resulted from additive genetic effects, and dominance and epistatic interactions were nonsignificant. Partitioning of the total genetic variance into those attributable to the effects of embryo, endosperm, testa and the cytoplasm indicated that additive effects of endosperm and embryo could individually account for 80% and 77% of the total variance, respectively. In the control treatment, greater than 60% of the variation could be explained by individual additive effects of endosperm or embryo and ? 27% of the variation could be explained by embryo dominance effects. Across generations, there was a positive correlation (r = 0.78, P < 0.01) between germination in the control and low-temperature treatments and there were no significant genotype × temperature interactions. The results indicate the presence of similar or identical genes with predominantly additive effects on germination under both low and high temperatures. In the second approach, the effectiveness of directional phenotypic selection to improve tomato cold tolerance during germination was evaluated by selecting (in an F₂ population of the same cross) the fastest germinating seeds under low temperature and comparing the germination of the selected F₃ progeny with germination of an unselected F₃ population. The results indicated that selection was highly effective and significantly improved germination performance of the progeny; a realized heritability of 0.74 was obtained for low-temperature tolerance during germination. It is concluded that in these tomato lines germination under low temperature is genetically controlled, with additivity being the major genetic component, and thus the trait can be improved by phenotypic selection.