番茄ps-2雄性不育系01222的育性观察

对从保加利亚引入并选出的含有番茄ps - 2基因的雄性不育新品系 0 12 2 2进行了杂交制种试验。结果表明 ,该不育品系虽然会发生自交 ,但座果率极低 ,其中正常果率只占 2 9% ,其余均为僵果。通过开花后 1～ 3d人工去雄授粉和蕾期去雄杂交制种试验比较说明 ,即使 3d后的处理杂交种子纯度仍可达 99%以上 ,符合国际种子质量标准 ,但是杂交座果率、单果种子含量却随开花天数的增加而降低 ,以蕾期和开花后 1d处理最佳。表明该不育系是一个很有应用价值的新材料。     

The use of genetic,manual and chemical methods to control pollination in vegetable hybrid seed production: a review

Production of hybrid varieties of vegetable crops is currently a desired breeding goal, due to their remarkable agronomic performance and to the possibility of intellectual property protection. However, efficient hybrid production requires a careful pollination control to guarantee the hybrid nature of F₁ seed. Several technologies ranging from manual emasculation to genetic transformation are used to inhibit pollen production in mother plants. In this review, we examine the principles underlying strategies like genetically determined systems (genic male sterility, cytoplasmic–genic male sterility, self‐incompatibility) and other methods (manual emasculation, chemical‐hybridizing agents) in different species, considering the benefits and drawbacks of their adoption. Finally, we present the current state of the art for vegetable hybrid seed production.     

Applications of Genie Male Sterility in Plant Breeding

The possible applications of genie male sterility (GMS) in plant breeding arc reviewed and discussed. The basic contribution of GMS is that it provides a means of genetic emasculation which can be applied for the massive production of hybrids. There are two main fields of application: (1) the production of hybrid varieties and (2) inter- and intraspecific hybridization and back-crossing programmes for the introduction of genetic variation into crop varieties. Several schemes have been proposed for using GMS in hybrid breeding in different crops. These are discussed under four headings: genetic methods, cy-togenetic methods, temporary restoration of fertility and manual pollination. The application of GMS in hybridization intended for the introduction of alien genes is discussed as well as factors affecting the pollination of genie male steriles.     

番茄花粉生活力研究

本研究从制种实践出发,对番茄花粉生活力曲线及影响花粉生活力的诸多因素--不同采花时间、干燥时间、干燥方式、贮藏方式进行了研究.结果表明:冀东番茄杂交制种适宜的时期是5月26日以后.标准蕾、较大蕾的花粉生活力极低,为适宜的去雄时期;盛开的花花粉生活力最强,为适宜的采花时期;开花当天上午的花粉生活力极显著高于下午的新鲜花粉生活力,但干燥至第2天早晨,二者无显著差异,故开花当天上午、下午采花均可;室内自然阴干是花药的最佳干燥方式,干燥时间以8 h内为宜;花粉贮藏以低温干燥法最好.     

棉花诱导长柱头杂交制种及配套技术研究

旨在减少棉花杂交制种用工,提高棉花杂交制种工效,降低棉花杂交种子生产成本。采用GA₃溶液诱导棉花长柱头,不去雄直接授粉;采用小型强磁高速电动机作为动力,研制小型田间快速采粉器,同时研制与采粉器配套使用的简易授粉器。通过多年的研究,研制出一种新的杂交棉制种新方法,即用100 mg/kg浓度的GA₃溶液,处理8~18天母本的幼蕾,每花点滴量150~200 μL,开花当天,不去雄父本花粉直接授予母本伸长的柱头上;研制出与之相配套的棉花快速采粉器和低温贮能式授粉器,操作简便,田间采粉速度快,授粉效率高,生产的杂交种子纯度在95%以上,符合国家良种要求。该研究将稳定的诱导技术与采粉器和授粉器结合应用于棉花杂交制种,可节省大量用工,综合提高制种工效30%以上。     

Agro-morphological characterization of ovary culture-derived plants of rice (Oryza sativa L.)

Plants derived from unpollinated ovary culture of ten rice genotypes showed significant variability in agro-morphological characteristics. The ovary-derived plant (H1) populations were completely haploid, doubled haploid or haploid-doubled haploid mixture. Haploids had very drastic reduction in plant height, panicle length, grain length, breadth and number and spikelet fertility (0.0%–2.1%). Doubled haploids from the hybrid of UPRI 95–121 × UPRI 95–165 were normal with fertility ranging between 69.6% and 97.7%. A genetic segregation in ratio of 1:1 was observed for five pigmentation characters in the H1 population derived from hybrid UPRI 95–122 × UPRI 95–165. Plant height showed the largest coefficient of variability (28.5%) followed by the number of spikelets per panicle (24.2%), number of grains per panicle (22.0%), percent seed set (9.2%) and panicle length (9.0%). The range of variation in the H1 population from fully fertile hybrid PMS 2A (CMS) × IR 31802 (restorer) was similar to its corresponding F2 population for plant height, spikelet fertility and number of grains/panicle. A single clone of plants from the cultivar BG 1321 exhibited complete male sterility but normal female fertility when pollinated with other varieties. Ovary-derived plants from the CMS lines PMS 2A and IR 58025A showed stable male sterility and those from thermosensitive genetic male sterile line UPRI 95–140 showed thermosensitive genetic male sterility. These lines have potential in the hybrid breeding program and are being currently exploited. This revised version was published online in July 2006 with corrections to the Cover Date.     

Modified complementation test of male sterility mutants in pepper (Capsicum annuum L.): preliminary study to convert male sterility system from GMS to CMS

The male sterility system in hybrid seed production can eliminate the cost of emasculation and ensure seed hybridity through avoidance of self pollination. GMS and CMS are two types of male sterility system that currently employed in pepper breeding. Conversion from GMS to CMS will increase the male sterility proportion of female parent from 50 to 100%. In this study, segregation analysis of four male sterile mutants consisting of one CMS mutant (CA1) and three GMS mutants (GA1, GA3 and GA4) showed that each had single recessive gene inheritance. A modified complementation test was performed by replacing male sterile mutants with their maintainer line as male parent. The nuclear restorer gene for CMS was independent of all nuclear restorer genes for GMS and all nuclear restorer genes for GMS were independent each other. Further observation on CMS and GMS male sterility loci revealed that GA1 and GA3 had mutated in both nuclear restorer genes for CMS and GMS, while CA1 and GA4 each carried mutation in single male sterility system of nuclear restorer gene for CMS and GMS, respectively. Conversion from GMS to CMS in the case of lines carried mutations in both sterility systems required only S-type cytoplasm donor, while lines carried mutation in single nuclear restorer gene for GMS required not only S-type cytoplasm but also rf allele donors. The important finding is the broader function of maintainer line in certain male sterility system that can be used as a maintainer or restorer line for other male sterility systems. We also confirmed that line CC1 is the general restorer for both CMS and GMS systems.     

A comparison of cytoplasmic and chemically-induced male sterility systems for hybrid seed production in wheat (Triticum aestivum L.)

A comparison of two male sterility systems was carried out in wheat for hybrid seed production and hybrid performance. Seventeen hybrid combinations based on Triticum timopheevi cytoplasm were compared with their genetically equivalent CHA-facilitated combinations. The same set of restorer lines was used as parents in CMS- and CHA-based hybrids to maintain genetic equivalence. In the first experiment aimed at study of female line behavior and crossed seed production, the CHA treated lines showed significantly shorter heights whereas CMS lines were similar to the control. The two systems were equally effective in sterilizing rate. The outcrossing percentage of the CMS lines was almost twice that of the CHA treated lines. Thousand-grain weight of the crossed seeds on CMS lines was greater than on the CHA treated lines and control. On average, the germination percentage of seeds on CMS lines was double that of the CHA treated lines and the percentage of effective outcrossed seeds in CMS lines was 3 times more than that from CHA treated lines. The second experiment was conducted to examine the yield performance of the hybrids derived from the two systems of male sterility. A total of 40 entries including 20 hybrids and 20 parents were evaluated in the experiment. The mean grain yield of the CMS-based hybrids was greater than that of the CHA-based hybrids,the B and R lines. All the CMS-based hybrids showed significantly higher grain yields than their better parents whereas all the CHA-based hybrids, except two,showed no significant yield increases over their better parents. Possible reasons for differences in CMS- and CHA-based hybrid performance are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

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.     

Hybrid reconstruction in maize

Summary The production of seed of the maize single cross hybrid F68^*NE2 is uneconomic because of the low grain yield of the maternal line. Therefore the aim was to produce it from newly developed inbred lines obtained by reshuffling the genes in the hybrid, accompanied by selection. Thus in open pollinating generations derived from this hybrid, i.e. in C0, C1, C2, C3 and C4, honeycomb selection for grain yield improvement was applied. Selfing of one ear and open pollination of another ear of selected prolific C4 plants yielded 20 pairs of S1/half sib progenies. Plants grown from remnant S1 seed corresponding to superior progeny pairs were selfed. In each S2-line a single plant was selected and selfed. The S3-lines were evaluated for yield. Two S3-lines, i.e. 6D and 2B, attracted attention because they yielded two and a half times as much as the best commercial inbred line B73.The S1-and S2-lines were tested for combining ability with the related inbred lines NE2 and F68 by means of honeycomb design experiments and for combining ability with unrelated, freely available inbred lines by means of randomized complete block designs. Two S2-lines, i.e. 5C and 6E, were selected for their good combining ability. The six single cross hybrids produced by crossing the four S3-lines 6D, 2B, 5C, and 6E were compared with the original hybrid F68^*NE2 in a honeycomb design at two sites. The grain yields of the single cross hybrids 6D^*6E and 5C^*6E were similar to that of F68^*NE2. However, these two reconstructed hybrids can be produced in a cheaper way because the new maternal inbred lines yield as good as B73 (line 5C) or much better (line 6D).     

Hybrid seed production in safflower (Carthamus tinctorius) following the induction of male sterility by gibberellic acid

The objective of the present research was to develop an effective and practical method for hybrid seed production in safflower, by inducing male sterility with gibberellic acid (GA₃). Seeds of the spiny line ‘5‐154’ and the non‐spiny variety ‘Dincer 5‐118’ were sown in alternate rows and the plants of the non‐spiny female variety were exposed to various concentrations of GA₃ for male sterility induction. Three successive sprays (75, 82 and 89 days after sowing) of 100 p.p.m. of GA₃ to safflower buds of <0.5 cm diameter at a pre‐meiotic interphase stage resulted in reduced pollen viability from 81.6‐6.7% compared with the control. An average hybrid seed percentage of 80.7% (87.5% in the secondary heads), identified by the use of the spiny‐capitulum marker variety ‘5‐154′, was obtained. The GA₃ treatments did not significantly affect the production of viable achenes. The results showed that GA₃ could be successfully used as a chemical hybridizing agent in hybrid safflower production.     

Some causes of variation in the proportion of selfed seed present in F1 hybrid seed lots of Brussels sprouts

Summary A series of field experiments on F₁ hybrid seed production was performed, using two parent inbred lines known to have incomplete self-incompatibility and thus to be susceptible to the production of some selfed seed. The experiments compared different ratios of plants of the two parents, different sub-lines, plant sizes and pollinating agents; and showed that all these treatments could cause changes in the ratio of selfed seed to crossed seed produced. The results are discussed in relation to the search for a mathematical model to express the basic factors likely to determine the rate of selfing in an F₁ hybrid seed production situation.     

Emasculation of Tartary buckwheat (<Emphasis Type="Italic">Fagopyrum tataricum</Emphasis> Gaertn.) using hot water

Hot water treatment was applied to Tartary buckwheat (var. ‘Hokkai T8’) for emasculation. Apical clusters of flower buds were soaked in a constant temperature water bath (42–44°C) in the afternoon and then the flowers which opened in the next morning were used for the investigation of self-fertilization and the artificial pollination. Hand pollination was carried out by rubbing the anthers taken from the male parent (var. ‘Hokkai T10’) to the stigma of the flowers treated by hot water. The seed set by self-fertilization was almost 0% when treated at 42°C for 8 min or more, at 43°C for 5 min or more and at 44°C for 3 min or more. With artificial pollination, the best performance was obtained when treated at 44°C for 3 min, in which the seed set was 55.1% and the matured seed was obtained 37.7% of the hand-pollinated flowers. Nine out of 26 progeny seedlings emerged and the cotyledonal color of them were all reddish green, probably indicating the hybrid of ‘Hokkai T8’ and ‘Hokkai T10’. The hybridization was reconfirmed by the segregation in F₂. The hot water treatment at 44°C for 3 min was available to other seven varieties. From 24.5% to 100% of the hand-pollinated flowers set mature seeds though only one self-fertilized seed remained without artificial pollinations. This hot water treatment must be practically useful in hybridization breeding of Tartary buckwheat.     

Possibilities of incompletely sib-incompatible inbred lines in breeding hybrid varieties of cole crops (Brassica oleracea L.)

Summary Until now most breeders have preferred fully sib-incompatible inbred lines when producing seed of hybrid varieties of cole crops. In this paper, however, the possibilities of incompletely sib-incompatible lines are discussed.Calculations are made of the ratio between SxSx, SxSy and SySy in the progenies of an SxSy-plant which is selfed for one generation and mass-propagated in further generations. The ratio between these genotypes and the generations in which an equilibrium is attained is determined by the relation between the S-factors and their activities.Lines produced in this way are incompletely sib-incompatible. With dominance between the S-factors in pollen or style or in both, the percentage of sibs, when using such lines for the production of hybrid seed, will be too high (> 10%). This percentage is much reduced, and with active S-factors may even be less than 1, if an independent relation exists between the S-factors. This small percentage of sibs is generally no serious handicap in producing hybrid seed for many practical purposes.     

Generation of tribenuron‐methyl herbicide‐resistant OsCYP81A6‐expressing rapeseed (Brassica napus L.) plants for hybrid seed production using chemical‐induced male sterility

Chemical‐induced male sterility (CIMS) is a method for hybrid rapeseed (Brassica napus L.) production. Some sulphonylurea herbicides such as tribenuron‐methyl (TBM) are used as chemical hybridization agents (CHAs) in CIMS systems. However, the male parents must be protected from herbicide injury with a shield during spraying of the female parents with CHAs to induce male sterility. Thus, using herbicide‐resistant rapeseed lines as the male parents can significantly simplify the seed production procedure and reduce the cost in hybrid seed production. A rice cytochrome P450 hydroxylase, OsCYP81A6, has been previously characterized to confer resistance to bentazon and sulphonylurea herbicides. We demonstrate here that the introduction of OsCYP81A6 renders rapeseed plants resistant to TBM. Compared with wild‐type plants, the transgenic plants displayed normal stamen development and male fertility when treated with 0.05 mg/l of TBM, the dose used for inducing male sterility in hybrid seed production. These results indicate that the OsCYP81A6‐expressing rapeseed plants can be used as the male parents for hybrid rapeseed production using CIMS.     

Genetic linkage between male sterility and non‐spiny trait in safflower (Carthamus tinctorius L.)

Genetic male sterility (GMS) exists naturally in safflower (Carthamus tinctorius L.). In the existing safflower GMS lines, sterile and fertile plants are distinguishable at flowering. This causes delay in fertile plants rouging and reduction in hybrid purity. In this investigation, a cross between a spiny GMS parent 13‐137 and a spiny non‐GMS parent ‘A1’ was effected. One sib cross, SC‐67, producing non‐parental‐type non‐spiny sterile and spiny fertile plants in F₃ was advanced to F₉ through sib crossing between non‐spiny sterile and spiny fertile plants. Mendelian digenic segregation was not observed for non‐spiny trait and male sterility. The results revealed strong linkage between these traits. The linkage was confirmed in F₂ generations of crosses between a non‐spiny marker‐linked GMS line (MGMS) and five elite lines. Male sterility–linked non‐spiny trait could distinguish sterile and fertile plants at elongation stage. The MGMS would be useful in production of pure F₁ hybrid seed and development of elite populations.     

BS系列杂交小麦在陕西渭南地区制种可行性分析

高效制种技术是杂交小麦推广和产业化的重要影响因素,适宜制种区域的探索是制种技术研究的关键内容。以往基于光温敏不育的BS系列杂交小麦制种区域较为单一,多集中在安徽阜阳地区。为扩充杂交小麦的制种区域,本研究将陕西渭南地区与传统制种区域——安徽阜阳种子生产区进行了生态气候条件比较分析。渭南地区小麦生长期平均温度较阜阳低1.3℃,育性转化重要时期平均温度相差小于1℃;日可照时数与原阜阳制种区相近,从光温等生态气候条件上为BS系列杂交小麦制种提供了可能。同时,渭南地区在小麦种子生产关键时期降水量较阜阳低41.7%,种子质量更有保障。在此基础上,在陕西渭南地区开展了BS系列光温敏不育系育性鉴定和中试制种试验。结果表明,大部分BS系列骨干不育系自交结实为0.5粒/穗左右,不育度可达98%以上;各杂交种平均异交结实数可达14.4~20.7粒/穗,制种产量超过3 000kg/hm ²,并且种子纯度达到95%以上,符合杂交小麦制种生产要求。渭南地区可作为BS系列杂交小麦制种的备选区域。     

A new male sterile mutant LZ in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Genetic male sterility (GMS) genes in wheat (Triticum aestivum L.) can be used for commercial hybrid seed production. A new wheat GMS mutant, LZ, was successfully used in the 4E-ms system for producing hybrid wheat, a new approach of producing hybrid seed based on GMS. Our objective was to analyse the genetic mechanism of male sterility and locate the GMS gene in mutant LZ to a chromosome. We firstly crossed male sterile line 257A (2n = 42) derived from mutant LZ to Chinese Spring and several other cultivars for determining the self-fertility of the F₁ hybrids and the segregation ratios of male-sterile and fertile plants in the F₂ and BC₁ generations. Secondly, we conducted nullisomic analysis by crossing male sterile plants of line 257A to 21 self-fertile nullisomic lines as male to test the F₁ fertilities and to locate the GMS gene in mutant LZ to a chromosome. Thirdly, we conducted an allelism test with Cornerstone, which has ms1c located on chromosome 4BS. All F₁s were male fertile and the segregation ratio of male-sterile: fertile plants in all BC₁ and F₂ populations fitted 1:1 and 1:3 ratios, respectively. The male sterility was stably inherited, and was not affected by environmental factors in two different locations or by the cytoplasm of wheat cultivars in four reciprocal cross combinations. The results of nullisomic analysis indicated the gene was on chromosome 4B. The allelism test showed that the mutant LZ was allelic to ms1c. We concluded that the mutant LZ has common wheat cytoplasm and carries a stably inherited monogenic recessive gene named ms1g.     

Nicotiana tabacum L. as a source of cytoplasmic male sterility in interspecific cross with N. alata Link & Otto

A new source of cytoplasmic male sterility (CMS) in tobacco with interspecific origin is reported. In traditional selection wild tobacco species have been used as donors of cytoplasm. In the present study the cultivated species Nicotiana tabacum L. (n = 24) is a source of CMS. It was used as female parent and N. alata (n = 9) was involved as a pollinator. The F1 hybrid of this cross was completely sterile. Tissue culture method was applied to restore the female fertility. Regenerants obtained from the 5th passage were successfully pollinated with N. tabacum and seed-containing capsules were formed. All BC1P1 plants were male sterile. They possessed normally developed corollas, three-loculed or deformed pistils, and 1–2 stamens modified into secondary pistils. In some plants stamenless flowers were observed. Male sterility of BC1P1 was preserved in BC2P1–BC7P1 progenies confirming its cytoplasmic nature. This revised version was published online in July 2006 with corrections to the Cover Date.     

Conversion of the genic male sterility (GMS) system of bell pepper (Capsicum annuum L.) to cytoplasmic male sterility (CMS)

Non‐pungent bell pepper (Capsicum annuum L.) lacks the cytoplasmic male sterility (CMS) nuclear restorer allele, Rf, and CMS cannot be employed in its F₁ hybrid seed production. To demonstrate that the genic male sterility (GMS) system in non‐pungent bell pepper can be converted to the CMS male sterility system, the conversion of GMS to CMS for non‐pungent bell pepper line GC3 was conducted by introgression of S‐type cytoplasm and the Rf allele from tropical pungent donors. After morphological traits were evaluated, two lines from BC₁F₁ containing S‐type cytoplasm and four lines from BC₂F₂ containing Rf allele, phenotypically similar to GC3, were obtained and could be employed as CMS male sterile lines and restorer lines for non‐pungent bell pepper. Four molecular markers potentially linked to traits of interest were also evaluated in BC₁F₁ and BC₁F₂ populations. This is the first time that GMS has been successfully converted to CMS in bell pepper, a significant contribution for bell pepper hybrid seed production.