The use of seed acid phosphatases in the determination of the purity of F1 hybrid brussels sprout seed

Summary Starch gel electrophoresis of single seeds of five different F₁ hybrids of Brussels sprouts showed that they possessed three cathodal acid phosphatases. By comparison with cathodal acid phosphatases present in their inbred parents these have been interpreted as the two parental types plus a hybrid enzyme. All of the parental material could be classified into two groups depending upon whether or not their cathodal acid phosphatase was fast or slow moving. It was shown that these acid phosphatases are suitable for the determination of sibs in F₁ hybrid sprout seed provided that one of the parents possesses the slow moving cathodal acid phosphatase and the other the fast moving one. A survey of 35 different F₁ hybrids showed that 18 could be analysed for sibs using this method, those which could not were assumed to have had parents who possessed cathodal acid phosphatases of the same mobilities.     

Application of isozyme electrophoresis for purity testing and cultivar identification of F1 hybrids of Brassica oleracea

Summary Six isozyme genes were analyzed in seed samples of 65 commercial F₁ hybrids of four horticultural groups of Brassica oleracea (cabbage, Brussels sprouts, sprouting broccoli and cauliflower). Results obtained from electrophoretic assays led to the following conclusions: 1) the electrophoretic test of F₁ hybrid purity was possible in 59 (91%) of the hybrids analyzed, since their inbred parents were apparently fixed each for a different allele in at least on of the loci studied; 2) forty-eight (74%) of the hybrids were individually distinguished by their isozyme phenotype; 3) high levels of segregation in the inbred parents were inferred from the analysis of a sample of seeds of each hybrid.     

Increased atmospheric humidity post pollination: A possible aid to the production of inbred line seed from mature flowers in the Brussels sprout (Brassica oleracea var. Gemmifera)

Summary In two highly self incompatible inbred lines of Brussels sprouts the effect of increased atmospheric humidity post pollination was examined immediately following 1) hand pollination of green buds and open flowers, and 2) blowfly pollination of open flowers. Data were obtained for mean number of seeds set per pollination, mean number of fruits setting seed, and mean number of seeds produced per fruit which set for both varieties. Measured as number of seeds produced per minute spent pollinating, it was clear that open flower pollination followed by high humidity conditions was a much more efficient method of producing inbred line seed (46 seeds/minute) than green bud pollination (27 seeds/minute).     

Isoenzyme and cotyledon protein variation for identification of black beans (Phaseolus vulgaris L.) with similar seed morphology

Summary Methods developed to identify genetically diverse varieties of beans (Phaseolus vulgaris L.) were applied to closely related lines that were difficult to distinguish on the basis of seed morphology. Seedling tissues and seeds of black beans, were examined electrophoretically for isoenzyme and cotyledon proteinn protein patterns. Seven enzymes, extracted from seeds or from seedling stem, root or leaf tissues, were compared for polymorphism. Peptidase, polyphenol oxidase, phosphoglucoisomerase and glutamate oxaloacetate transaminase patterns were the same for all lines. Some differences were observed for acid phosphatase, peroxidase and esterase patterns, but complete discrimination of the six selected lines was not possible on the basis of isoenzyme patterns alone. Using polyacrylamide gel electrophoresis (PAGE) of dissociated 0.1 M acetic acid soluble proteins at pH 3.1 (acid-PAGE), or sodium dodecyl sulphate PAGE (SDS-PAGE) of residual protein extracts, all but one pair of samples in each case could be distinguished from the other samples. Using both techniques all of the lines could be identified unequivocally.     

Inbreeding and the production of commercial F1 hybrid seed of brussels sprouts

Inbred lines, many of which have reached or passed the I₄ generation, have been produced by successive generations of self-pollination of material selected stringently for desirable characteristics. Of 99 parent plants originally selected from three different non-inbred varieties only eight were represented in the I₄ generation, by which time individual inbred lines were virtually true breeding for characters of commercial importance.An F₁ hybrid named Avoncross, produced by crossing unrelated selected inbred lines, has given consistently good yields of high quality sprouts in trials grown during several seasons. In most of these trials Avoncross gave the greatest marketable yield as compared with various control varieties and its superiority was significant at the 5% level of probability. A further F₁ hybrid, as yet un-named, has also given promising results in recent trials.Genetic male sterility was found in the material but did not provide an economic method for the production of F₁ hybrid seed. The method developed for the field production of F₁ hybrid seed relies on natural crossing between partially sib-compatible inbred lines. The partial sib-compatibility makes it possible to multiply the parent inbred lines by using natural sib-pollination in the field, but leads to the presence of sibs in the F₁ hybrid seed produced by natural crossing. The percentage of sibs in field crops of the F₁ hybrid established from such seed, however, was acceptably low because the majority of the sib-seedlings initially present could be rejected, on the basis of their smaller size, at the time of transplanting from the seedbed to the field.Experimental seed production, both of parent inbred lines and of the F₁ hybrid Avoncross, indicated that commercial production of F₁ hybrid seed in this manner was likely to be economically feasible.     

Seed storage potential of population varieties and hybrid varieties and their breeding components in rye (Secale cereale L.)*

Seeds of population varieties, hybrid varieties, cytogenetic male sterility (CMS) single cross lines and CMS inbred lines of rye (Secale cereale L.) were stored to determine the respective rates of germination loss with a view to their storage potential. The seeds were stored under controlled conditions at a seed moisture content of 14% and a temperature of 30°C for periods of up to 80 days. The storage potential decreased in the order: hybrid varieties > population varieties > CMS single cross lines > CMS inbred lines. However, the rates of germination loss showed no differences within the respective categories. The inferences drawn for seed storage potential hold for seed vigour potential.     

Inbred lines with dominant incompatibility alleles for use as parents of F1 hybrid brussels sprouts

Summary To improve the chances of obtaining highly self-incompatible inbred lines for use as parents of F₁ hybrid Brussels sprouts and to extend the range of mutually cross-compatible combinations available, new inbred lines are being produced from plants selected for the presence of dominant S-alleles. The material comprises 42 different inbred families representing 15 cultivars and contains 12 dominant S-alleles of uncommon occurrence in Brussels sprouts. Data on S-allele interactions in the material are presented.Tests showed that whilst many of the parent plants containing dominant S-alleles were highly self-incompatible, a few had only weak self-incompatibility. Although the chances of obtaining strongly self-incompatible inbreds may be increased by using material with dominant S-alleles, it remains necessary to test and select for strong self-incompatibility during the breeding programme.Production of such inbred lines requires the application of two independent selection procedures, one for agronomic type and one for S-allele constitution. Only a small proportion of the plants of a parent cultivar are acceptable on both counts. Thus large populations of the cultivar and large numbers of selections are necessary: this in turn involves much expensive S-allele screening. To alleviate this problem a wide-based panmix containing only dominant S-alleles is being produced. It is hoped that from this it will be possible to extract inbred lines which carry only dominant S-alleles, so avoiding the need to screen each parent plant for its S-allele content.     

Variation of flowering time in inbred brussels sprouts and cabbage (Brassica oleracea L.)

Summary Differences in time of flowering between two parent lines of F₁ varieties of Brassica oleracea could significantly affect both the total seed yield and the proportion of sibs in the hybrid seed crop.The results for the time to flower of an incomplete diallel show that even in relatively inbred material of brussels sprouts there is potential to select for altered flowering time. Results obtained from a set of highly inbred cabbage lines which were given three temperature regimes in early spring show that between line variation is complicated by different responses of some of the lines to the environments.     

Selection for seed set capacity uncorrelated with flower heteromorphism in Primula vulgaris Hudson

Within-line pollinations were used when measuring the seed set of plants from seven early generation inbred lines of Primula vulgaris. One high seed setting plant and one low seed setting one were selected from each line and the seed set was evaluated on the offspring from selfings and within-line pollinations of these plants. Regression of offspring on parents for seed set was studied. The slope was estimated to be 0.17 ± 0.08, equivalent to an estimated heritability of around 34%. No significant differences in the slope of regression between the two reproduction methods (selfings or within-line pollinations) were detected. The realized improvement through one cycle of selection of high seed setting single plants in this early generation inbred material of P. vulgaris was 23.7%. Analysis of the seed set of within-line pollinated clones from late generation inbred lines of P. vulgaris revealed that only limited within-line variation remained after removal of the effects of the heteromorphic incompatibility system. It was concluded that selection of high seed setting single plants during early generations of inbreeding is efficient for improvement of seed set in future inbred lines of P. vulgaris to be used for hybrid seed production.     

Use of immature seed germination and single seed descent for rapid genetic gains in pigeonpea

Long duration required for generation advancement in pigeonpea [Cajanus cajan (L.) Millsp] is one of the major bottlenecks in realizing rapid genetic gains. Therefore, a technology for rapid generation turnover is warranted to facilitate the development of new cultivars and recombinant inbred lines. Breeding of early‐maturing cultivars has now opened up the possibility of rapid generation advance (RGA) in this crop. This paper reports the development of an RGA technology that integrates the germination of immature seeds with single seed descent method of breeding. The results showed that immature 35‐day‐old seeds can be used successfully to turn over a generation of pigeonpea with 100% seed germination. These way 3/4 successive generations can be grown within a year. The methodology presented in this study will accelerate the breeding process for breeding cultivars and develop rapidly the materials required for genomics research in pigeonpea.     

Mapping of quantitative trait loci controlling seed longevity of rice (Oryza sativa L.) after various periods of seed storage

Seed longevity varies considerably in cultivated rice (Oryza sativa L.), but the underlying genetic mechanism of longevity has not been well elucidated. Quantitative trait loci (QTL) that control seed longevity after various periods of seed storage were sought using recombinant inbred lines derived from a combination involving ‘Milyang23’(Indica‐type) and ‘Akihikari’ (Japonica‐type). In all, 12 QTLs for germination and normal seedling growth were detected as indices of seed longevity on chromosome 7 (one region) and chromosome 9 (two regions) in treated seeds that had been stored under laboratory conditions for 1, 2 or 3 years.‘Milyang23’ alleles of all QTLs promoted germination and normal seedling growth after all durations of storage. These QTL regions were detected repeatedly in more than one seed condition. Therefore, we infer that these regions control seed longevity.     

Inheritance and linkage of a gene for testa-imposed seed dormancy in faba bean (Vicia faba L.)

Seed dormancy in the grain legumes may interfere with germination in some situations, yet is not well described. Dormancy in faba bean (Vicia faba L.) was investigated to determine the mode of inheritance and whether the gene or genes controlling this trait are linked to other genes. Seeds produced by 235 recombinant inbred lines at the F₆ generation were used for this study. The parents were the cultivar ‘Optica’ and 172, an Afghanistan landrace which possesses extended seed dormancy. Germination was scored on a seed sample from each recombinant inbred line. Segregation patterns indicated that the trait is monogenic. This gene, named doz, is linked to a gene controlling anthocyanin and proanthocyanidin synthesis, sp-b, with the genetic distance estimated to be about 25 cM. No associations were detected between seed dormancy and pod dehiscence, seed lustre or mean seed weight. The implications of the persistence of a gene for seed dormancy in the gene pool of V. faba for the introgression of traits from landraces and cultivars possessing dormancy and for the origins of domesticated V. faba are discussed.     

Factors affecting the degree of self-incompatibility in inbred lines of Brussels sprouts

Summary Experiments were made in which four different lines of Brussels sprout, each homozygous for S-allele 2, were tested for self-incompatibility at various stages of plant and flower development under different environmental conditions. The tests were made by counting the number of pollen tubes present in the style 24 hours after pollination, by means of the Ultra-violet Fluorescence technique.The results showed that the degree of self-compatibility varied widely, being greatest during the middle to late stages of the flowering period, at the highest temperature treatment applied. No mean differences could be detected between the effects of self- or sib-pollination; or between pollination of flowers of different ages.One of the inbred lines showed a greater response than all the others to the highest temperature at a late stage of flowering. Under these conditions this inbred line showed more than a tenfold increase in the number of tubes growing after self-pollination, as compared with the overall mean of the experiment. This result is interpreted as indicating a modifying effect of the genetic background on the expression of the major S-allele. On the basis of the results obtained, methods are suggested for more efficient selection of inbred lines of Brussels sprouts with strong and stable self-incompatibility behaviour.     

Selection for high self-incompatibility in inbred lines of brussels sprouts

Summary An attempt to improve the self-incompatibility of an advanced inbred line of Brussels sprouts by selection has been unsuccessful. The apparent plant-to-plant variation in self-incompatibility has little or no genetic basis. It results from environmental effects and from intrinsic physiological differences between flowers on a single plant. A temperature rise from 17°C to 26°C markedly increases the self-compatibility of the lines tested, but no evidence was found for end-of-season compatibility. The best methods for producing inbreds with high and consistent self-incompatibility are discussed.     

Carbon dioxide treatment as an effective aid to the production of selfed seed in kale and Brussels sprouts

Summary The use of carbon dioxide to overcome the self-incompatibility mechanisms in marrow-stem kale and Brussels sprouts (Brassica oleracea L.) is discussed. Results are presented to show the effectiveness of the treatment, and a method is described of applying it as a routine procedure for the production of selfed seed in quantily.     

Varietal identification in Cichorium intybus L. and determination of genetic purity of F1 hybrid seed samples, based on RAPD markers

Random amplified polymorphic DNA (RAPD) markers were used to distinguish between several Cichorium intybus genotypes, comprising four white witloof inbred lines, three red witloof experimental inbred lines and a number of F1 hybrids derived from two white parents. Amplification conditions and reproducibility of RAPD patterns were examined. Comparison of polymerase chain reaction (PCR) products obtained by using 100 10-mer arbitrary primers allowed identification of all the lines analysed. With several primers, we defined line-specific RAPD markers, while with others polymorphism was more extensive, revealing several RAPD markers for several lines. All the differences were confirmed both on individual heads and young seedlings for each genotype. Because of the Mendelian segregation of these molecular markers, this method was applied to evaluate the genetic purity of F1 hybrid seed samples.     

Evaluation of important seed and sprout traits as potential selection criteria in breeding varieties for sprout soybeans

Soybean sprouts, a traditional vegetable in Asia, are gaining popularity in the United States. Soybean sprout demand has been supplied by natto (a Japanese soyfood) cultivars that share some seed characteristics with sprout cultivars. However, natto seeds do not meet all requirements of sprouts and are rejected by sprout manufacturers. The objectives of this study were to evaluate important seed and sprout traits as potential selection criteria in breeding sprout soybeans and to study the storage effect on soybean sprout quality. Almost all genotypes produced thicker and longer hypocotyls and higher fresh-sprouts than ‘MFS-561’, a commercial soybean sprout variety. Hypocotyl length ranged from 13.8 to 16.2 cm. Four fungi genera Bipolaris sp., Cercospora sp., Botrytis sp. and Caethomium sp. were isolated from seeds. Cracked cotyledons and abnormal seedlings were the two main constraints affecting soybean sprout quality. Correlation coefficients among all traits indicated that percentage and weight of high- and average-quality sprouts would determine sprout yield. Acceptable yield and several traits were recommended to be used simultaneously while breeding superior sprout soybean cultivars. Good sprout varieties should produce high-quality sprouts >48%, average-quality sprouts <38%, low-quality sprouts <14%, sprout yield >5.7 g/g seed, hypocotyl thickness >1.6 cm and hypocotyl length >13 cm. One-year seed storage at room temperature reduced sprout quality. V09-3876 and V12-1939 had superior seed and sprout traits and are promising lines for further evaluation for sprout production. Seed storage over time affects seed germination and seedling vigor, and fungi on seed can cause reduced seed quality.     

等电聚焦同工酶电泳技术鉴定甘兰一代杂种纯度

等电聚焦丙烯酰胺凝胶电泳方法分析了京丰一号、中甘十一甘兰一代杂种及双亲幼苗的过氧化物同工酶,共分离出12条谱带,两个杂交组合F_1杂种与亲本间同工酶图谱表现出明显不同,均为互补型差异。在此基础上,我们开展了应用等电聚焦电泳技术对甘兰杂交种纯度的检测,并同时在田间进行验证性测定,酶谱纯度和田间纯度二者回归方程式为y=7.93 0.93x,相关系数r=0.96.对r进行t测验t=4.47>2.79(t_(0.01)=2.79,n=26),表明同工酶测定和田间测定结果之间存在着极显著的正相关关系。     

Development of photoperiod-sensitive cytoplasmic male sterile (PCMS) wheat lines showing high male sterility under long-day conditions and high seed fertility under short-day conditions

A “two-line system” using photoperiod-sensitive cytoplasmic male sterility (PCMS) caused by Aegilops crassa cytoplasm under long-day photoperiods (≧15 h) has been proposed as a means of producing hybrid varieties in common wheat (Triticum aestivum). The PCMS line is maintained by self-pollination under short-day conditions, and hybrid seeds can be produced through outcrossing of the PCMS line with a pollinator line under long-day conditions. Our previous studies revealed that PCMS lines showing complete male sterility under long-day conditions are necessary for practical hybrid wheat breeding, especially to obtain high hybrid purity in F₁ seeds. Furthermore, practical PCMS lines should have high seed fertility under short-day conditions, which is associated with female fertility. Wheat cv. Norin 26 with Ae. crassa cytoplasm exhibits high seed fertility under short-day conditions, and cv. Fujimikomugi with Ae. crassa cytoplasm shows high male sterility under long-day conditions. Here we developed practical PCMS lines derived from the F₁ generation of Norin 26 and Fujimikomugi (with Ae. crassa cytoplasm) that were then backcrossed to elite wheat lines.     

利用清蛋白多态性鉴定玉米种子纯度研究

利用改进的聚丙烯酰胺凝胶电泳技术,对生产上应用的53个玉米杂交种及亲本自交系干种子清蛋白(白蛋白Albumin)进行了电泳分析。结果表明,改进的聚丙烯酰胺凝胶电泳技术分辨率高、鉴别能力强、准确;不仅能鉴别杂交种及亲本自交系,对血缘关系较近的材料,如同母异父单交种、含有同一血缘的不同衍生系也能区分开。利用该技术