Heterosis and combining ability analysis in Chinese semi-winter × exotic accessions of rapeseed (<Emphasis Type="Italic">Brassica napus</Emphasis> L.)

Fourteen accessions (spring and winter types) and four testers (semi-winter type) of rapeseed (Brassica napus L.) were crossed in line?×?tester mating design to estimate general and specific combining ability for seed yield, yield components, and oil content. The F₁ hybrids and their parents were evaluated in four environments in northern China. Highly significant differences were detected among the parents and hybrids for all the traits across environments. Plant height, setting position of first primary branch and length of terminal raceme were controlled by additive genes, whereas primary branches per plant, siliques on terminal raceme, siliques per plant, seeds per silique, seed yield per plant, 1000-seed weight, oil content, and seed yield were controlled by non-additive gene action. The accessions SP-Armada, 9E49, and CZ25 and the tester Zhong9 were good general combiners for seed yield. Among the 56 F₁ hybrids, four hybrids: Zhong9?×?CZ25, GZ1R?×?9E38, Zhong7?×?9E38, and Zhong7?×?CZ49 showed higher yield than the control and were the outstanding combinations for seed yield. These hybrids were recommended to be included in future breeding programs for development of new high yielding varieties with more desirable traits. Both winter and spring germplasm have potential in Chinese semi-winter rapeseed breeding program, for seed oil content improvement, more attention may be paid to spring germplasm.     

Genetics of Seed Yield and Its Components in Common Beans (Phaseolus vulgaris L.) of Andean Origin

A broad spectrum of rapeseed (rape) lines as well as resynthesized (resyn) genotypes of B. napus were analyzed for their contents of sinapoyl esters. In the rape material the concentrations varied between 17.8 and 71.9 μol/g defatted seed meal and exhibited a heritability of h²= 0.6. The resyn genotypes showed an even smaller variation but had a similar heritability. Therefore, no additional, immediately usable, genotypes with low sinapoyl ester concentrations could be created by a resynthesis.     

Heterotic patterns in rapeseed (Brassica napus L.): II. Crosses between European winter and Chinese semi-winter lines

Chinese semi-winter rapeseed is genetically diverse from European winter rapeseed. Our objectives were (1) to evaluate the potential of semi-winter rapeseed for winter rapeseed hybrid breeding, (2) to assess the relative importance of general combining ability (GCA) vs. specific combining ability (SCA) among combinations between Chinese semi-winter and European winter rapeseed, and (3) to compare the strategies to predict heterosis based on parental genetic distance (GD) estimated from AFLP marker data and GCA for hybrid performance. Four winter male sterile lines from Germany as testers were crossed with 14 Chinese semi-winter rapeseed lines to develop 56 hybrids, which were evaluated together with their parents and commercial hybrids for seed yield, oil content and protein content under three environments in Germany. The Chinese parental lines were not adapted to local environmental conditions as demonstrated by lacking winter hardiness and poor seed yields per se . However, the hybrids between the Chinese parents and the adapted winter rapeseed lines exhibited high heterosis for seed yield. About 20% of the hybrids were significantly superior to the respective hybrid control under three environments. Additive gene effects mainly contributed to hybrid performance since the variance components of GCA were higher as compared with SCA. The correlation between parental GD and hybrid performance was found to be low whereas the correlation between GCA and hybrid performance was high and significant, with correlation coefficients of 0.95 for seed yield, 0.87 for oil content, and 0.91 for protein content, indicating that GCA can predict hybrid performance. These results demonstrate that Chinese semi-winter rapeseed germplasm has a great potential to increase seed yield in winter rapeseed hybrid breeding programmes in Europe.     

Yield Performance of New European Spring Rapeseed (Brassica napus L.) Cultivars Under Winter Season Cultivation in Egypt

The present investigation was undertaken on four W. German (AD201, Belinda, Korina and Elvira) and five French (Cresor, Brutor, BRO, BRIO and Orpal) spring rapeseed varieties, for evaluation and to study their performance and productivity under Fayoum (Egypt) conditions during two successive winter seasons (1982/1983 and 1983/1984). In order to make clear identification for different plant characters, some genetical parameters were estimated.
In the first season, the nine varieties were arranged into a randomized complete block field experiment with four replications. In the second one, the experiment (with the same design and replication) included only six cultivars, after elimination of three winter-type (Belinda, Korina and Elvira) that failed to reach flowering because of unique cold temperature requirements. Therefore, the present study was restricted with the remainder six varieties.
The varieties exhibited considerable differences in all the characters studied. AD201 was earlier, higher seed- and oil-yielding variety than other tested ones. Its superiority could be attributed to increased number of pods/plant, seeds/pod and seed yield/plant. The second yielding variety was BR1O followed by Cresor, BRO and Brutor. While Orpal was inferior in all characters except for seed index. Data showed that fruiting zone length reached nearly half the mature height for each genotype.
Remarkable amount of genotypic variation and high heritability estimates were recorded for all studied characters. Quantitative analysis indicated that number of seeds/pod, early flowering, seed weight/plant, possessed high heritability values combined with high genetic gains and wide genetic variations. By these characters, discernible improvement could be easily achieved through phenotypic selection in relatively very short time.     

Combining ability estimates for yield and fibre quality traits in 4 × 13 line × tester crosses of Gossypium hirsutum

The aim of this study was to estimate the general combining ability of the parents and specific combining ability of hybrids considered for the development of high yielding and better quality cultivars. Seventeen genotypes and 52 F₁ hybrids obtained by crossing 4 lines and 13 testers in line × tester mating system during 2003 were sown in randomized complete block design in 2004. Line × Tester analysis revealed significant GCA and SCA effects for all the traits except fibre elongation. Preponderance of non-additive gene action was obtained for seed cotton yield per␣plant and majority of its component traits including fibre traits. Among the parents: PIL-8 for days to 50% flowering, CCH-526612 for boll weight, CITH-77 for number of open bolls per plant and CNH-36 for seed cotton yield per plant were detected with higher general combining ability. Parent, CCH-526612 for 2.5% span length, fibre strength and fibre elongation and AKH-9618 for micronaire value, fibre strength and fibre elongation were good combiners for fibre quality traits. The F₁s achieved high seed cotton yield by producing more number of open bolls. The high yielding hybrids with acceptable fibre quality traits were: CISV-24 × LH-1995, H-1242 × PIL-8 and RS-2283 × SGNR-2 deducted with significant SCA effects for seed cotton yield and fibre characteristics; 2.5% span length and fibre strength. These cross combinations involved at least one parent with high or average GCA effect for a particular trait.     

以半冬性甘蓝型油菜为亲本增强春性甘蓝型油菜杂种优势

以春性恢复系与半冬性品种(系)杂交后选育的16份新春性恢复系及其4个亲本系[2个半冬性甘蓝型油菜品种(系)和2个春性甘蓝型恢复系]、2个春性甘蓝型不育系为材料, 利用SSR、SRAP和AFLP分子标记技术分析材料间的遗传差异, 同时利用以上2个春性不育系分别与12个新春性恢复系和1个春性亲本恢复系Ag-5进行NCII双列杂交, 测定其杂种优势及杂种表现。16份新恢复系中除931和帐23外, 其余的14份新恢复系与2个不育系的遗传距离均大于其春性亲本恢复系与相应不育系的遗传距离, 说明导入半冬性品种遗传成分能扩大春性恢复系与不育系间的遗传差异; 配制的26个杂交组合中, 其双亲中不育系所对应保持系单株产量为高亲值的组合有15个, 其中13个组合单株产量超亲优势都强于所对应不育系与亲本恢复系Ag-5所配杂交组合, 说明导入半冬性品种遗传成分可增强甘蓝型春油菜杂种优势; 12个新恢复系分别与2个不育系所配24个组合中18个组合的单株产量都分别超过所对应不育系与亲本恢复系Ag-5所配杂交组合, 说明导入半冬性品种遗传成分能提高甘蓝型春油菜杂种的产量; 新恢复系与2个不育系杂交后代的抗病性均强于其亲本恢复系与相应不育系杂交后代的抗病性, 说明导入半冬性品种遗传成分能提高春性甘蓝型油菜杂交种抗菌核病的能力。研究结果表明, 半冬性甘蓝型油菜品种可能为春油菜杂交育种提供有价值的遗传资源。     

Introgression of reproductive traits from Trifolium nigrescens increases the seed yield of white clover (T. repens)

Interspecific hybrids between white clover and the annual, profuse flowering ball clover have been developed as a strategy to improve the potential seed yield of white clover. The seed yield and seed yield components of advanced white clover × ball clover hybrids were compared with white clover in replicated field experiments over two harvest years. The backcross 3 hybrid had more reproductive nodes per stolon than the control variety ‘AberHerald’ which was reflected in more inflorescences per unit area but inflorescences with fewer florets and seeds. The hybrid had a greater potential seed yield than the control variety in 2002 but not 2001. Backcross 3 hybrids have also been produced across the range of leaf size categories. Medium and large leaved hybrids produced significantly more inflorescences and a higher potential seed yield than control varieties of comparable leaf size in both harvest years. The small leaved hybrid was not significantly greater than the control variety ‘AberDale’ in either inflorescence production or seed yield.     

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     

Identification of QTLs for salt tolerance at germination and seedling stage of Sorghum bicolor L. Moench

Upland cotton (Gossypium hirsutum L.) hybrids display commercially useful levels of heterosis for lint yield. Cotton lint yield is primarily a multiplicative product of boll number and lint per boll, both of which can be further dissected into sub-components. Relationships among the yield components are complex where they further interact with the environment. To identify different yield components of hybrid cotton lint yield and their relationship with environment, three cotton varieties, DP51, STV474 and LA887 and, their respective hybrids were evaluated for lint yield components across five environments. Heterosis was observed for lint yield as well as yield components. The relationship between heterosis and mean environmental yield was negative for two hybrid combinations, whereas one hybrid showed increased heterosis from low to high yielding environments. Boll number was the major yield component contributing to lint yield. However, yield components contributing to the change in heterosis from low to high yielding environments were different for the three hybrids. The change in lint yield heterosis across environments was correlated with lint per boll and lint per seed for DP51 × STV474 and LA887 × DP51. Whereas, bolls number and boll retention were the main yield components contributing to higher lint yield heterosis of STV474 × LA887 in low yielding environments. Results also reveal effects of parental entries on lint yield as well as relationship of heterosis and environment.     

Yield stability and adaptability of canola (<Emphasis Type="Italic">Brassica napus</Emphasis> L.) in multiple environment trials

Selecting high yielding genotypes with stable performance is the breeders’ priority but is constrained by genotype × environment (G×E) interaction. We investigated canola yield of 35 genotypes and its stability in multiple environment trials (MET) in south-western Australia and the possibility to breed broadly-adapted high yielding genotypes. The Finlay–Wilkinson (F–W) regression and factor analytic (FA) model were used to investigate the G×E interaction, yield and genotype stability and adaptability. The cross-over response in the F–W regression, substantial genetic variance heterogeneity, and the genetic correlations in the FA model demonstrated substantial G×E interaction for yield. Cluster analysis suggests low, medium and high rainfall mega-environments. F–W regression indicated that genotypes with high stability (e.g. low regression slope values) produced relatively low yield and vice versa, but also identified broadly adapted genotypes with high intercepts and steep regression slopes. The FA model provided a more detailed analysis of performance, dividing genotypes by positive, flat or negative responses to environment. In general, early flowering genotypes responded negatively to favourable environments and vice versa for late flowering genotypes. More importantly, a few early flowering hybrids with long flowering phases were consistently productive in both low and high yielding environments, showing broad adaptability. These productive hybrids were consistent with those identified earlier by high F–W intercept and slope values. Hybrids were higher yielding and more stable than open-pollinated canola, as was Roundup-Ready^® canola compared to the three other herbicide tolerance groups (Clearfield^®, Triazine tolerant, conventional). We conclude that yield stability and high yield are not mutually exclusive and that breeding for broadly adapted high yielding canola is possible.     

春油菜区优质高油高产高抗型油菜品种的示范推广

【目的】为了提高春油菜区油菜生产的商品性、高效性和市场竞争力,使优良品种得到推广应用。【方法】通过育种家+种子公司+基地+农户+科技的机制模式对高油高产优质高抗型油菜品种“鸿油88”在春油菜主产区进行试验示范推广。【结果】结果表明：“鸿油88”在春油菜主产区表现出较强的抗旱性、丰产性、稳定性,具有抵御高温干旱的能力,相对增产潜力大。【结论】从根本上解决春油菜区油菜生产的效益最大化,保障油菜安全生产和供给。     

Genetic Structure of Three Open-Pollinated Faba Bean Varieties (Vicia faba L.)*

To study the genetic structure of open-pollinated faba bean varieties, three sets of genotypes were generated from each of the varieties ‘Minica’, ‘Kristall’, and ‘Deiniol’: (1) inbred lines developed by single-seed descent in bee-proof isolation cages, (2) intravanetal and (3) intervarietal F₁-hybrids produced by controlled hand crossing. In 1989 and 1990, a total of 144 entries, including the three open-pollinated source varieties, were grown in single-row plots with two replications at two locations in Western Germany. Performance data of the inbred lines revealed relatively large genotypic variability within each variety, for all the characters studied, which was greater in ‘Deiniol’ and ‘Kristall’ than in ‘Minica’. An average yield heterosis of 20 %, 39 % and 57 %, respectively, was found for the intravarietal hybrids, whereas that of the intervarietal hybrids varied between 70 and 73 %. Compared to the mean yield of the inbred lines the superiority of the open-pollinated source variety was small and not significant in ‘Minica’ (6 %), but it was large and highly significant in ‘Kristall’ (22 %) and ‘Deiniol’ (37 %). The present investigation revealed in faba bean that similar performance levels of open-pollinated varieties may result from either high per se performance under inbreeding with low heterosis values or from lower per se performance but with high heterosis values.     

Seven years experience with hybrid tomatoes

Summary From 1950 to 1956 a total number of 196 hybrids was tested in coldhouses. After continuous selection eleven commercially acceptable hybrids remained. In comparison with commercial varieties all these eleven hybrids showed the advantage of stronger vegetative development, higher yielding capacity and higher early yield; two of them moreover possessed a better disease resistance.Generally we may conclude that the advantages of good hybrids, if grown in Dutch coldhouses, only result in a relatively small financial advantage; the higher early yield is obtained between the middle of July and the beginning of August, a period of low, nearly constant prices. On the other hand, on account of the much higher prices before the month of July a higher early yield of hybrids, grown in a heated glasshouse, will result in a much greater commercial advantage.With hybrids, adaptation to changes in growing and market conditions can be obtained rapidly. Good examples are leaf mould resistant hybrids of Ailsa Craig strains x Vagabond and a better nematode resistant hybrid of Ailsa Craig x H.E.S. 4245.Crosses of Dutch commercial varieties with parents originating from countries with a warmer climate, gave disappointing results under unfavourable weather conditions.In order to obtain outstanding early hybrids it is necessary to breed better early yielding parents, with good combining ability.     

Heterosis and Genetic Variances and their Implications for Breeding Improved Varieties of Spring Beans (Vicia faba L.)*

Handcrosses were made in a factorial manner with 24 Vicia faba inbred lines m three sets, each between four male and four female parents. The resulting 48 hybrids, their parental inbreds and three commercial varieties were grown in performance trials during the years 1985—87 with three replications at one location. Yield and yield components were recorded on single plant basis. The average superiority of the hybrids above the control varieties was 26 % in plant yield. The best crosses outyielded the controls by more than 50 %. However, a few inbred lines also reached, the yield level of the controls. The average heterosis was significant for all characters except for maturity date. In plant yield the average heterosis was 75%, ranging between 34% and 148% in the various cross combinations. The highest average heterosis of 110 % was observed in yield at the lateral stems. In all characters the best inbreds were superior to the lower hybrids and in some characters even equal to the average of the hybrids. A strong positive relationship was found for all characters between hybrid performance and mid-parent value and between the per se performance of the inbreds and their general combining ability. Genotypic differences between the hybrids as well as between the inbreds were highly significant. Most of the variability between the hybrids in all characters were attributed to general combining, ability with only little evidence for specific combining ability. In the discussion the results are evaluated according to the choice of the breeding category of the partial allogamous faba bean species.     

优异纤维品质陆地棉和转基因抗虫棉的杂种优势和亲子相关性

利用32个优异纤维品质陆地棉品种和8个转基因抗虫棉品种杂交配制了62个F1,研究F1的杂种优势强度及亲子相关性。结果表明:抗虫杂交棉具有极强的产量优势,在构成因素中,单铃重的优势最大,其次是衣分,而成铃数、子指表现为负优势。纤维品质性状的中亲优势较小,但具有较强的对照优势。抗虫棉F1的单铃重、纤维品质性状与双亲呈显著正相关。生育期、衣分性状只与父本呈显著正相关,果枝数与母本显著正相关,株高、成铃数等5个性状与双亲相关均未达到显著水平。     

An evaluation of an index method of selection for high yield in turnip rape,Brassica campestris L. ssp. oleifera Metzg

Summary Substantial variation in yield, its primary components and several vegetative characters which influence yield was observed among a series of families drawn at random from a low erucic acid variety of turnip rape. A sib analysis of family means showed all characters to have relatively high heritabilities, although yield was, together with seed weight and specific leaf weight, in a group having the lowest values.Several characters, including flowering time, leaf area and leaf weight, had appreciably higher heritabilities than yield, however, none appeared to be a suitable alternative criterion for selection as the expected correlated responses to selection for these characters were lower than the direct response to selection for yield. The expected genetic advance in yield from the simultaneous selection for a number of these characters using a selection index technique, was significantly greater than that expected from selection for yield alone. Selection indices based either on yield components or vegetative characters were, at best, only as efficient as selecting directly for yield. Several indices including measurements of both yield components and vegetative characters were, however, expected to facilitate a greater rate of advance in yield than direct selection.The practical value of such indices in improving rapeseed yields in Western Australia was discussed with reference to the additional costs involved in their use and their accuracy in environments where genotype x environment interactions are likely to be high.     

Sources of parthenocarpy for Zucchini breeding: relationship with ethylene production and sensitivity

Cytoplasmic genic male sterility system based hybrids were synthesized by line × tester design and evaluated with check GTH 1 in RBD at Sardarkrushinagar, Jagudan and Khedbrahma during kharif 2007. Analysis of variance in individual and across environments revealed significant differences among genotypes and existence of overall heterosis for seed yield per plant and other thirteen traits. The top ranking on the basis of standard heterosis were CMSGT087A × GTR0525 (116.40 %) followed by CMSGT087A × AGTR0534 (108.93 %), CMSGT0307A × AGTR0538 (99.21 %) and CMSGT 0301A × AGTR 0534 (95.51 %) for seed yield per plant and for one or two of its contributing traits. Combining ability analysis revealed presence of both additive and non-additive gene effects. The specific combining ability variance was found more compaired to general combining ability variance for all the characters under studied. This favored a hybrid breeding programme. In stability analysis, linear portion was considerably high for all the traits except for days to flower and pod length. The best stable hybrids for seed yield per plant over environments were CMSGT 308A × AGTR 0534, CMSGT 307A × AGTR 0543, CMSGT 0308A × AGTR 0536 and CMSGT 0311A × GTR 0525 and also recorded stability in any one or more of its contributing traits viz. pods per plant, branches per plant, seed per pod, pod length and test weight. Top ranking hybrids had high mean performance, high heterosis and desirable sca effects and stability for seed yield per plant. Therefore, these hybrids could be valuable for commercial exploitation.     

陆地棉显性无腺体品系杂种优势及配合力研究

以７个显性无腺体陆地棉品系和４个常规品种（系）为材料，按ＮＣＩ设计，对２８个组合的杂种Ｆ１进行了分析。结果表明。杂种Ｆ１具有明显的优势，２８个组合所研究的１５个性状中全部具有中亲优势，６个性状具有高亲优势，４个性状具有竞争优势；配合力分析的１１个性状中，株高、衣分、纤维长度和麦克隆值主要受基因加性效应控制，而子棉产量、皮棉产量、单株铃数、铃重和子指等性状同时受基因加性和非加性效应作用，显无０７３是丰产的显性无腺体品系，而显无２６０是较好的优良品系，组合显无０７３Ｘ泗棉２号在重要性上表现较好。     

Impact of low linolenic acid content on seed yield of winter oilseed rape (Brassica napus L.)

An essential quality improvement of rapeseed oil can be obtained by reduction of its linolenic acid (C18:3) content from about 10% to less than 3% of the total fatty acids. Genotypes low in C18:3 have been developed by mutagenesis. The initial summer rapeseed mutant had been low yielding and highly susceptible to various diseases. It has been debated whether the low C18:3 character can be successfully combined with high seed yield for physiological reasons. Therefore, the low linolenic character of mutant M48 was transferred into high-yielding genotypes by repeated backcrossing to well-adapted low erucic acid, low glucosinolate (00-) winter rapeseed cultivars. Lines with low C18:3 content were selected from BC3 and BC4 generations and examined in 1990–95. Positive selection response for seed yield was shown to continue over the years. Presently, the best lines are yielding as well as the control cultivars being equivalent also in oil and glucosinolate contents. In order to test the effect of a low C18:3 content on seed yield, plants with low and with high C18:3 content, respectively, were selected from 16 segregating BC5-F₂ populations and bulked to form 32 F₃ populations. These ‘isogenic’ bulk populations were tested for field performance at four locations in 1995. The results show that C18:3 content of the seed oil is not associated with seed yield, oil content, beginning of flowering, plant height and disease resistance. Means of relative seed yield for the high and the low linolenic F₃ bulk populations were not significantly different with 88.0% and 86.9% of the control cultivars, respectively. There was a significant interaction between genotypes with high or low C18:3 content and location. This shows that under specific environmental conditions a low C18:3 content may be either favourable or unfavourable. The results indicate that the low C18:3 character of the original mutants per se does not cause a decrease in seed yield, oil content or general field performance.     

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.