Cytoplasmic male sterile and doubled haploid lines with desirable combining ability enhances the concentration of important antioxidant attributes in <Emphasis Type="Italic">Brassica oleracea</Emphasis>

The Brassica vegetable crops are rich source of important antioxidant compounds having anticancer and health promoting properties. Development of F₁ hybrids with better nutritional traits is one of the main breeding objectives in different vegetable crops. Our study is the first report of determining heterotic combinations utilizing cytoplasmic male sterile (CMS) and doubled haploid (DH) inbred lines for antioxidant compounds in snowball cauliflower. Twenty genetically diverse Ogura CMS lines of cauliflower and six DH male fertile inbred lines were crossed to develop 120 F₁ hybrids in line?×?tester mating design. The resulting 120 test cross progenies along with 26 parents and 4 standard checks were evaluated in 10?×?15 alpha lattice design with three replications during next cropping season. The CMS lines Ogu33-1A, Ogu122-5A and Ogu119-1A were good general combiner and CMS line Ogu118-6A was poor general combiner for majority of traits. Most of the heterotic hybrids were associated with high positive SCA effects. The proportions of σ²A/D and \(\upsigma^{2}_{\text{gca}} /\upsigma^{2}_{\text{sca}}\) ratios were less than unity in all the cases indicating preponderance of non-additive gene action in the genetic control of all the traits. Highest number of heterotic hybrids with SCA effects in desired positive direction was recorded for ascorbic acid content and phenolic content followed by total carotenoid content. The F₁ hybrids with better combining ability and better per se performance could be useful in accumulation of favourable allele for higher concentration of important anti-oxidant compounds.     

Superior CMS (<Emphasis Type="Italic">Ogura</Emphasis>) lines with better combining ability improve yield and maturity in cauliflower (<Emphasis Type="Italic">Brassica oleracea</Emphasis> var. <Emphasis Type="Italic">botrytis</Emphasis>)

Three CMS lines, Ogu1A, Ogu2A and Ogu3A were selected among ten lines after BC₇ based on superior commercial, floral and seed setting traits. Introgression of sterile Ogura cytoplasm in cauliflower nuclear background reduced the flower size but did not affect commercial and seed setting traits drastically. Line × Tester analysis was done by taking these three CMS lines free from floral deformities as female parent with nine diverse lines of snowball cauliflower as tester. The parent Ogu2A exhibited highest GCA effect for curd yield (4.51) and harvest index (1.97) while Ogu1A exhibited highest GCA for earliness (−2.73). The parent, Ogu2A exhibited significant GCA for curd length (0.39) while, none of the CMS lines showed significant GCA for curd diameter and depth. Heterosis for curd yield was highest in the hybrid, Ogu2A × Kt-22 (63.5%) followed by Ogu1A × WF (36.9%) and Ogu1A × Kt-15 was the best hybrid for earliness followed by Ogu3A × Kt-22 with heterosis of −14.4% and −11.7%. However, the number of heterotic hybrids for yield and earliness was low indicating narrow genetic base of the snowball cauliflower.     

Alteration in important quality traits and antioxidant activities in Brassica oleracea with Ogura cybrid cytoplasm

In vegetable brassicas, cytoplasmic male sterility (CMS) system is the most preferred mechanism for hybrid seed production and Ogura cybrid cytoplasm is the only source used widely. Effects of the alien cybrid cytoplasm on important quality traits need to be understood for their effective use in breeding programme. In analysing 38 Ogura cybrid cytoplasm‐based cauliflower CMS lines, it was revealed that introgression of Ogura cytoplasm resulted in significant alteration in important quality traits. Cupric reducing antioxidant activity and ferric reducing ability of plasma values were increased up to 5–10 times in different genotypes. Among 38 analysed CMS lines, concentration of plant pigments such as anthocyanin, total chlorophylls and ascorbic acid was reduced in 21, 17 and 32 genotypes, respectively. However, the concentration of total carotenoids and β‐carotene was elevated in most of the CMS lines and total carotenoid was increased up to 20 times in the CMS line, Ogu13‐85‐2A. The results indicate the role of nuclear–cytoplasmic interaction and mitochondrial genome in determining concentration of different quality traits.     

甘蓝型油菜双低萝卜质不育恢复系快速改良技术研究

通过采取不同的常规育种策略和小孢子培养、分子标记辅助选择等现代生物技术,研究了提高甘蓝型油菜萝卜质不育恢复系改良效率的方法。结果表明,在甘蓝型油菜萝卜质不育恢复系杂交转育过程中,采用杂交后代与萝卜质不育系杂交,可使杂交后代分离群体中不具备恢复基因的单株在花期表现出来,无须测交即可进行选择;杂交后代通过小孢子培养,可将稳定纯合时间由传统自交8个世代缩短到3个世代;通过萝卜特异分子标记辅助选择可大大提高选择的精度,减少筛选所需的人力、土地和时间,选择效率提高90%。试验筛选出19个在萝卜质不育恢复系中能够扩增出单一、易于辨别的谱带的SCAR标记引物,其中10个引物在现有的甘蓝型油菜萝卜质不育恢复系中均能检测出特异标记。筛选出的甘蓝型油菜萝卜质不育恢复系的特异分子标记与前人研究存在差异,标记相似系数为48.28%~93.10%。通过分子标记无法区分高硫甙和低硫甙恢复系,选育低硫甙萝卜质不育恢复系还需要借助品质分析仪。成功筛选得到6个甘蓝型油菜低芥酸、低硫甙、抗寒、结角正常、农艺性状优良的萝卜质不育恢复系,为将甘蓝型油菜萝卜质不育杂种优势应用于我国油菜生产奠定了基础。     

Advanced cycle pedigree breeding in sunflower. II: combining ability for oil yield and its components

Combining ability is one of the most important information breeders use to identify superior inbred lines on the basis of their performance in hybrid combinations. The objectives of our study were (i) to quantify the importance of general combining ability (GCA) and specific combining ability (SCA) variances for seed yield, oil content and oil yield; and (ii) estimate GCA and SCA effects of seed yield, oil content and oil yield of inbred lines developed from advanced cycle pedigree breeding populations in sunflower. A total of 109 female S₃ cytoplasmic male sterile (CMS) lines from four bi-parental populations in advanced cycle pedigree breeding were crossed with two testers to form 218 testcross hybrids (TCHs). The TCHs were then evaluated in three environments. Variance component analysis results showed predominance of σ²gca over σ²sca for seed yield and oil yield indicating that superior TCHs can be identified based on positive and significant GCA effects of the female lines. For oil content σ²sca was predominant over σ²gca indicating that selecting for TCHs with high oil content would be best among line × tester combinations and not among female S₃CMS lines per se. The proportion of GCA and SCA effects in the best five TCHs in each breeding population also confirmed the predominance of GCA effects over SCA effects for seed yield and oil yield while for oil content both GCA and SCA effects appear to be important, with SCA effects having more influence than GCA. The best selection strategy would therefore be to capture the GCA in the early stages of inbreeding and then SCA for the few unique combinations when lines are almost fixed.     

Inheritance of sugar and acid contents in the ripe berries of a tetraploid × diploid grape cross population

Pearl millet [Pennisetum glaucum (L.) R. Br.] is a major warm-season cereal, grown primarily for grain production in the arid and semi-arid tropical regions of Asia and Africa. Iron (Fe) and zinc (Zn) deficiencies have been reported to be a food-related primary health problem affecting nearly two billion people worldwide. Improving Fe and Zn densities of staple crops by breeding offers a cost-effective and sustainable solution to reducing micronutrient malnutrition in resource poor communities. An understanding of the genetics of these micronutrients can help to accelerate the breeding process, but little is known about the genetics and heterosis pattern of Fe and Zn densities in pearl millet. In the present study, ten inbred lines and their full diallel crosses were used to study the nature of gene action and heterosis for these micronutrients. The general combining ability (GCA) effects of parents and specific combining ability (SCA) effects of hybrids showed significant differences for both of the micronutrients. However, the predictability ratio (2σ²gca/(2σ²gca + σ²sca)) was around unity both for Fe and Zn densities, implying preponderance of additive gene action. Further, highly significant positive correlation between mid-parent values and hybrid performance, and no correlation between mid-parent values and mid-parent heterosis confirmed again the predominant role of additive gene action for these micronutrients. Barring a few exceptions with one parent, hybrids did not outperform the parents having high Fe and Zn levels. This showed that there would be little opportunity, if any, to exploit heterosis for these mineral micronutrients in pearl millet. In general, high Fe and Zn levels in both of the parental lines would be required to increase the probability of breeding high Fe and Zn hybrids.     

Inheritance of photosynthesis in a diallel among eight maize inbred lines from Iowa Stiff Stalk Synthetic

Summary Photosynthesis is a trait that should be improved in a selection program for yield potential of maize (Zea mays L.). We measured leaf CO₂-exchange rate (CER), an estimate of photosynthetic efficiency, of a complete diallel (parents, F₁ crosses, and their reciprocals) among eight inbred lines (4 with low and 4 with high CER) from the Iowa Stiff Stalk Synthetic maize population. Measurements were made during vegetative (CER 1) and grain filling (CER 2) stages of growth, and the experiment was conducted two years at one location. We measured large differences among crosses and significant heterosis for high CER at CER 1 (0.0 to 25.1%) and CER 2 (0.0 to 53.8%). Several crosses exhibited overdominant phenotypes for high CER at both growth stages, and one cross showed significant overdominance for low CER at CER 1. General combining ability effects (gca) were the largest components of among-cross variation at both CER 1 and CER 2. Specific combining ability (sca) also was significant at both growth stages, but gca effects were 9.4 and 4.8 times larger than sca effects at CER 1 and CER 2, respectively. Furthermore, high CER lines showed positive gca effects, and low CER lines showed negative gca effects at each stage. Maternal and reciprocal effects were not significant; thus, CER in these crosses was controlled largely by additive effects of nuclear genes. A high positive genotypic correlation (r=0.74) between CER 1 and CER 2 suggested that selection at either growth stage would improve CER throughout the growing season.Journal Paper No. J-9023 of the Iowa Agriculture and Home Economics Exp. Stn., Ames, Iowa. Project No. 1990.     

高粱籽粒蛋白质及其组份的配合力与杂种优势分析

本文以格里芬双列杂交模式Ⅱ设计,分析了高梁籽粒粗蛋白质含量及其4种组份和赖氨酸、色氨酸含量的配合力与杂种优势。结果表明,粗蛋白、清蛋白、球蛋白、谷蛋白、醇溶谷蛋白、赖氨酸含量等6个品质性状的σ_(gca)~2和σ_(sca)~2均达1％或5％显著平准,受加性和非加性基因效应的共同作用,其中加性基因效应作用占优势;色氨酸含量     

Assessment of cytoplasmic effects of cytoplasmic male-sterile lines in upland cotton

Paired A- and B-lines, cytoplasmic male-sterile (CMS)-lines and main-tainer lines, respectively, were crossed with R-lines (restorer) to produce A × R, R × B and B × R hybrids, which were used in 1993 and 1996 to predict the performance of three lypes of CMS cotton lines available in China. A significant difference in yield and yield components was revealed between paired A × R and B × R hybrids. This difference was greatly influenced by both CMS cytoplasm and the interaction between cytoplasm and nuclear genotypes. It is suggested that there are detrimental effects of CMS cytoplasm on yield and yield components. General combining ability of near-isogenic CMS lines was also affected by this negative effect. The detrimental effect was closely related to an increased number of immature seeds per boll, which might be caused by partial female sterility associated with CMS cytoplasm. The possibility of developing specific combinations of CMS Upland × Upland restorer hybrids that express enough heterosis for yield to overcome the detrimental effect of the CMS cytoplasm is discussed.     

Self-compatibility and heterosis in white clover (Trifolium repens L.)

Inbred lines of white clover (Trifolium repens L.) have been produced utilising the rare self-fertility (Sf) allele. Twenty-two lines of four distinct groups have been maintained through five generations of selfing by single seed descent. Fourteen lines were used in crosses to produce F¹s. Both parents and hybrids were analysed for a range of morphological characters. Positive heterosis for dry matter production was observed in half the hybrids. No other trait showed significant heterosis. The degree of heterosis appears to be related to the extent of variation in morphological characters between the parental lines, some combinations of lines yielding heterotic hybrids in all cases, others in none. The majority of the F¹ hybrids are superior in terms of dry matter production to eight control varieties. This revised version was published online in July 2006 with corrections to the Cover Date.     

Are ordinal rating scales better than percent ratings? a statistical and “psychological” view

Cytoplasmic male sterility (CMS) is considered an efficient genetic tool in pearl millet hybrid breeding. Of the several CMS sources available in pearl millet, A₁ is the only CMS widely exploited to produce commercial hybrids in India. To explore the possibility of using alternate CMS sources, we studied the cytoplasmic effects of different CMS sources on agronomic characters in pearl millet. Five CMS (A) lines representing A₁, A₂, A₃, A₄ and A₅ cytoplasms, their respective maintainer (B) lines and eight restorer (R) lines were used to generate 40 A × R and B × R experimental crosses. The experimental material was evaluated at two different locations in India. Analysis of combining ability and heterosis revealed that A₄ and A₅ cytoplasms had desirable effects for earliness. The A₅ CMS was found to be particularly promising, as compared to other CMS sources for improving grain yield. The study also indicated that the cytoplasmic effects on general combining ability (GCA) for various agronomic characters were largely non-significant. However, cytoplasmic effects on specific combining ability and heterosis were found to be modulated by cytoplasmic-nuclear interactions and influenced by the environmental conditions. The study also demonstrated the advantage of utilizing diverse male-sterile and restorer combinations in maximizing the productivity as well as for genetic and cytoplasmic diversification of hybrids in pearl millet.     

大白菜CMS96细胞质雄性不育分子特性研究

大白菜CMS96细胞质不育系是由大白菜株系与甘蓝型油菜细胞质不育源杂交、多代回交后获得的。该不育系生长势旺、不育性稳定,不育度和不育株率均为100%,蜜腺正常,在大白菜杂种一代生产中具有广阔的应用前景。为了定位大白菜CMS96细胞质不育所属的类型和获得其不育有关的特异序列,依据atp9、coxI、orf138和orf224保守序列设计4对引物,对3组11份大白菜材料线粒体DNA进行PCR扩增,每组材料内包含同核异质PolCMS、OguCMS、CMS96三种大白菜不育系和一种共用保持系。结果表明,atp9和coxI引物在所有材料中均有扩增产物,供试材料间没有差异;而orf138和orf224引物扩增产物存在差异。orf138引物仅在全部OguCMS和CMS96不育系中扩增出309bp特异带,而保持系和PolCMS不育系没有扩增产物;orf224引物仅在所有PolCMS中扩增出689bp特异带,而保持系、OguCMS和CMS96不育系没有扩增产物。同时,对保持系和不育系花组织mRNA进行RT-PCR分析,进一步验证了orf138和orf224引物扩增产物的特异性和一致性。同源性分析结果表明,利用orf138引物所获得的309bp大白菜mtDNA特异片段均与萝卜OguCMS、甘蓝型油菜OguCMS萝卜体细胞杂种所具有的Oguorf138高度同源,二者有172个核苷酸完全相同,有58个氨基酸完全相同;orf224引物所获得的689bp大白菜mtDNA特异片段与甘蓝型油菜的Polorf224高度同源,二者有677个核苷酸完全相同,有225个氨基酸完全相同,同源性均达到100%。初步认为大白菜OguCMS和CMS96不育系具有相似性,OguCMS萝卜所具有的orf138是导致二者不育的原因;Pol甘蓝型油菜所具有的Polorf224是导致大白菜PolCMS不育的原因。     

十字花科芸薹属种间杂种营养优势的利用研究

选用4个油菜雄性不育系和三种类型十字花科芸薹属种, 研究了不同杂交组合的亲和性, 杂种一代的营养优势表现和杂种营养优势的生理基础以及品质性状表现. 结果表明: 利用油菜雄性不育系与其它十字花科芸薹属种间杂交可以显著提高种间杂交的亲和性, 并具有细胞质遗传效应. 通过杂交制种可以获得大量的杂种应用于生产. 十字花科     

Combining abilities of in vitro traits in wheat (Triticum aestivum L.) immature embryo cultures

Summary Combining ability for six in vitro culture traits in wheat were studied in a 8×8 diallel cross (excluding reciprocals). Specific combining ability effects (sca) were significant for all six traits derived from immature embryos on two media protocols, whereas general combining ability (gca) variances were significant only for five of them. Furthermore, based on ratios obtained by comparing the ratio of K² gca to K² sca, sca was more important than gca for all six traits. Genetic correlations between shoot formation and other in vitro traits, except callus weight and root formation, were higher in magnitude than the corresponding phenotypic correlations estimates, indicating the importance of genetic effects.     

油菜胞质不育类型相关基因研究进展

细胞质雄性不育在油菜杂种优势利用中具有重要作用,研究细胞质雄性不育的不育机理对有效利用杂种优势,实现三系配套及创造强优势组合具有重要意义。介绍Ogu CMS,Pol CMS,Nap CMS等目前国际上主要的甘蓝型油菜细胞质雄性不育类型,综述了线粒体基因组上与CMS性状相关基因的位点或片段的最新研究进展,并讨论当今学术界有关CMS产生机理的主要论点。     

Identifying heterotic groups and testers for hybrid development in early maturing yellow maize (Zea mays) for sub-Saharan Africa

Identification of heterotic groups and efficient testers, which are important prerequisites for the development of outstanding hybrids, has been a major challenge to its success, especially for early and extra-early germplasm. This study was carried out to (a) identify the most efficient heterotic grouping method for classifying a set of inbred lines and (b) determine the efficiency of testers in classifying inbred lines into heterotic groups. A total of 205 hybrids obtained by crossing 41 inbred lines with five standard testers were evaluated together with five hybrid checks under drought, low soil nitrogen (N), Striga-infested and optimal environments in Nigeria between 2014 and 2016. The heterotic group's specific and general combining ability (HSGCA) method was more effective in classifying the inbred lines into heterotic groups. Testers TZEI 17 and TZEI 23 were the most efficient across environments and could be invaluable for classifying other lines into heterotic groups and assessing combining ability of maize inbreds. In addition, these testers and heterotic groups represent an invaluable resource for development of outstanding hybrids in sub-Saharan Africa (SSA).     

Studies on "Three Line" Polima Cytoplasmic Male Sterility Developed in Brassica napus L.

Polima CMS lines can be divided into three groups according to the sensitivity of male sterility to temperature: 1) high temperature CMS lines (62.9%), 2) low temperature CMS lines (28.6 %) and 3) stable CMS lines (8.5 %). The heterosis of Pol CMS hybrids is evident and common in some of the characters tested, especially in plant seed yield and siliqua number. The cytoplasm has no deleterious effects on the FI characters tested.     

Use of androgenesis in intersubspecific hybrid rice breeding

Significant differences of callus induction, green plant regeneration and culture efficiency were observed among restorer lines and their hybrids in rice. Average callus induction percentage of F₁, hybrids was about twice that of their parents. Twenty doubled haploid (DH) lines that showed normal fertility with both indica and japonica CMS lines, were selected as widely compatible restorers (WCRs). TG8 derived from CPSLO17/Minghui 63 not only showed normal fertility to both indica and japonica test varieties and CMS lines, but also exhibited superior agronomic traits, in particular short plant, desired plant type, high tillerability, large panicles, good grain quality and resistance to rice blast disease. Strong heterosis for yield was observed in crosses between indica or japonica CMS lines and TG8. TG8 possessed a dominant, widely compatible gene (WCG) that was inherited from the variety CPSLO17. Results confirmed that the anther culture technique is a quick and effective way of developing widely compatible restorers in rice and that it is applicable to the direct use of intersubspecific heterosis with the three-line method.     

杂交水稻产量及农艺性状杂种优势分析

为探讨杂种优势与双亲值、双亲一般配合力（GCA）、组合特殊配合力（SCA）、双亲遗传距离的关系,利用10个不育系和10个恢复系,按不完全双列杂交配制100个组合,对杂交水稻产量及农艺性状的杂种优势进行了分析,探索杂种优势的预测方法。结果表明：杂种一代的超亲优势和对照优势主要体现在穗长、每穗总粒数、每穗实粒数几个性状上,其具有正向超亲优势组合的比例分别达到61.0%、66.0%和53.0%,具有正向对照优势的比例分别为62.0%、78.0%和79.0%,结实率性状具有正向对照优势的比例也达到58.0%。杂种优势与父母本值、父母本平均值、高亲值、低亲值及父母本差值都有较为密切的关系,超亲优势与高亲值在8个性状上都极显著相关;对照优势与母本值、父母本平均值、高亲值都呈显著或极显著正相关。杂种优势与SCA和亲本的GCA效应值密切相关,特别是对照优势与SCA和双亲的GCA都呈显著或极显著正相关,同时与父母本的GCA之差和之和都有较大的关系。杂种优势与遗传距离的关系比较复杂,当遗传距离在5~5.5范围内,双亲的距离越远,杂种优势越强。     

Genetics of yield, quality and shelf life characteristics in tomato under normal and late planting conditions

Seventy nine genotypes of tomato (15 lines, four testers and their 60 F₁ hybrids produced in line × tester fashion) were evaluated under normal (E₁) and late planting (E₂) conditions in the Department of Vegetable Crops, Punjab Agricultural University, Ludhiana, India, to determine the nature of gene action controlling yield, quality and shelf life characteristics and to identify a few good combiner genotypes which may be used in further breeding programmes to extend the fruit availability period of tomato in North Indian plains. The lines were significantly different from testers for most of the characters thereby justifying the choice of testers. Additive gene action was predominant for days to ripening, total yield per plant, marketable yield per plant, number of fruits per plant, average fruit weight, fruit shape index and lycopene in both the environments, whereas non-additive genetic variance predominated in controlling firmness index, number of locules, pericarp thickness, alcohol insoluble solids (AIS), dry matter, total soluble solids (TSS), titratable acidity, TSS:Acid ratio, pH, ascorbic acid and shelf life, under both normal and late planting conditions. The best general combining ability (gca) effects, among females, in respect of yield per plant were shown by Spectrum in E₁ and by LT-42 in E₂. Among the testers, the best gca values in both the environments were possessed by nor-RM-1 for total yield per plant, marketable yield per plant, number of fruits per plant, dry matter and TSS; by rin-RM-2 for firmness index, pericarp thickness and alcohol insoluble solids; by alc-IIHR-2050 for average fruit weight, number of locules and shelf life and by alc-IIHR-2052 for lycopene. The gca of ripening mutants had a nice consonance with their per se performance for most of the characters indicating that additive gene action was operative in these mutants for majority of the traits.