Inheritance of Seed Dormancy in Lisianthus (Eustoma grandiflorum)

The genetics of chill-related seed dormancy, exhibited by a lisianthus (Eustoma grandiflorum) genotype native to North America, was investigated. Less than 1 % of the seeds germinated by direct hydration at 20°C, while full germination (98%) was attained by chilling imbibed seeds, for at least 11 days, at 3°C, before transferring them to 20°C. The inheritance of seed dormancy was analyzed in F₁, BC₁, and F₂, populations, derived from mating between a normal non-chill-requiring genotype (P₁) and the above chill-requiring genotype (P₂). F₁ seeds, of both reciprocals, and BC₁ (P₁) seeds were all non-dormant. The proportion of seed dormancy in F₂ and BC, (P₂) was 0.06 and 0.68, respectively. The inheritance model proposed includes six diallelic loci with cumulative effects, in which the presence of at least nine ‘dormancy-conferring’ alleles is necessary for inducing phenotypic seed dormancy. Possible implications of inherent seed dormancy on the utilization of native lisianthus germplasm for breeding are discussed.     

Genetics of Seed Yield and its Components in Common Bean (Phaseolus vulgaris L.) of Middle-American Origin

Genetic variance, heritability, and expected response from selection arc useful in devising alternative methods and criteria of: selection. The objectives of this study were to estimate these for seed yield and its components from 200 F₂: populations involving 80 cultivars and lines of mostly small-seeded dry bush bean (Phaseolus vulgaris L.) of habits growth I, II, and III of Middle-American origin. All cultivars and lines were crossed in eight sets of ten parents each in a Design II mating system. The F₂ populations, without parents, were evaluated in the field in a replicates-in-sets design at two locations in Colombia in 1983. Estimates of additive genetic variance were significant for yield, pods/m², seeds/pod, and seed weight. Interaction with environments was also significant. Values for nonadditive genetic variance were not significant for either yield or yield components. The estimates of narrow sense heritability, based on the F₂ population mean and unbiased by genotype x environment interaction, were 0.21 ± 0.13 for yield. 20 ± 0.13 for pods/m², 0.57 ± 0.13 for seeds/pod, and 0.74 ± 0.15 for seed weight. The expected direct response from selection of the top 20 % of F₂ populations for yield per se would result in a 4.30 % increase in yield with a correlated response of 0.21 % in seed weight. In contrast, the expected gain from direct selection for seed weight would result in a 11.76 % increase in seed weight with a, correlated gain of 0.28 % for yield. Direct selection for pods/m² would decrease yield, seeds/pod and seed weight, while direct selection for seeds/pod would reduce pods/m² and seed weight but increase seed yield by 0.37 %. Data on yield from replicated trials in the early segregating generations could be utilized for identification and selection of promising crosses and families or lines with crosses for dry bean yield improvement.     

Inheritance of shelf life and other quality traits of tomato fruit estimated from F<Subscript>1</Subscript>’s,F<Subscript>2</Subscript>’s and backcross generations derived from standard cultivar, <Emphasis Type="Italic">nor</Emphasis> homozygote and wild cherry tomato

A tomato cultivar with high quality fruit and a long shelf life is a main goal in tomato breeding and it would be achieved using wild germplasm. The objective of this work was to explore the inheritance for fruit quality traits, especially fruit shelf life, in three tomato crosses using a standard Argentinean cultivar (Ca, cv ‘Caimanta’), a ripening mutant (nor, homozygous for the nor gene) of Solanum lycopersicum, and a wild cherry type (Ce, LA1385 of S. lycopersicum var. cerasiforme). The wild parent had a shorter fruit shelf life than the mutant genotype but higher than Ca. When the Ce genotype was analyzed in hybrid combination, the F₁ (Ca×Ce) was similar to the wild genotype for shelf life whereas the F₁ (nor × Ce) had a longer shelf life. Both F₁ crosses and backcrosses to the cherry type genotype had significantly lower fruit weight than the cultivated genotypes but higher than the cherry type parent. In the F₂ analysis, it was found that the inheritance underlying quality traits is complex since non allelic interactions were detected. A significant additive genetic variance was found for fruit shelf life as well as for other fruit quality traits in each cross. The genetic parameters analyzed by mean values and variances in parental, F₁ and F₂ and backcross generations indicated that the cross between the normal ripening cultivar and LA1385 of S. lycopersicum var. cerasiforme offers the best possibility to obtain long shelf life tomato genotypes with good fruit quality.     

Inheritance of seed colour in Brassica campestris L. and breeding for yellow-seeded B. napus L.

Summary Seed colour inheritance was studied in five yellow-seeded and one black-seeded B. campestris accessions. Diallel crosses between the yellow-seeded types indicated that the four var. yellow sarson accessions of Indian origin had the same genotype for seed colour but were different from the Swedish yellow-seeded breeding line. Black seed colour was dominant over yellow. The segregation patterns for seed colour in F₂ (Including reciprocals) and BC₁ (backcross of F₁ to the yellow-seeded parent) indicated that the black seed colour was conditioned by a single dominant gene. Seed colour was mainly controlled by the maternal genotype but influenced by the interplay between the maternal and endosperm and/or embryonic genotypes. For developing yellow-seeded B. napus genotypes, resynthesized B. napus lines containing genes for yellow seed (Chen et al., 1988) were crossed with B. napus of yellow/brown seeds, or with yellow-seeded B. carinata. Yellow-seeded F₂ plants were found in the crosses that involved the B. napus breeding line. However, this yellow-seeded character did not breed true up to F₄. Crosses between a yellow-seeded F₃ plant and a monogenomically controlled black-seeded B. napus line of resynthesized origin revealed that the black-seeded trait in the B. alboglabra genome was possibly governed by two independently dominant genes with duplicated effect. Crossability between the resynthesized B. napus lines as female and B. carinata as male was fairly high. The sterility of the F₁ plants prevented further breeding progress for developing yellow-seeded B. napus by this strategy.     

Inheritance of siliqua orientation and seed coat colour in Brassica tournefortii

The inheritance of siliqua orientation and seed coat colour in Brassica tournefortii was investigated using four genotypes varying in these two characters. The F₁, F₂ and backcross generations of two crosses were used for studying the segregation pattern of the traits. The plants were classified for seed colour as having brown or yellow seeds and for siliqua orientation as having upright, semi‐spread or spread siliqua. Seed colour was found to be under monogenic control with brown being dominant over yellow. Siliqua orientation was under digenic polymeric gene action: upright siliqua was produced by the presence of two dominant genes and spread siliqua by two recessive genes. The absence of even a single dominant gene resulted in a third type of siliqua orientation, semi‐spread siliqua.     

Durum Wheat under Mediterranean Conditions as Affected by Seed Size

This study was carried out in order to determine the effect of seed size on the growth and yield of durum wheat. Four field experiments, composed of six durum wheat (Triticum turgidum L. var. durum) varieties and three seeding sizes were conducted in north‐east Spain in 2000 and 2001 in randomized complete block designs. The growth of seedlings was dramatically affected by seed size. Large seeds produced greater plot stands, but the plants had fewer tillers, leaves and spikes and less green area and dry weight than plots from small seeds. Grain yield was 16 % greater in plots from large seeds, which resulted in greater biomass, green area index, spikes per m² and heavier kernels than in plots from small seeds. Kernel weight was the yield component most related to grain yield in the three seed sizes. The percentage of yield variation explained by kernel weight increased as the weight of kernels increased. This was a consequence of the use of larger seeds, the same effect being observed when the comparison was made between varieties with different kernel weights. Selection for heavy kernel varieties may help to improve the yield of durum wheat in Mediterranean environments similar to that prevailing in north‐east Spain.     

Micropropagation of intra and interspecific Lens hybrids

An intraspecific (Tetir × ILL 323) and an interspecific (Alpo × L. odemensis) lentil hybrid were multiplied in vitro in three consecutive micropropagation cycles to increase the production of F₂ seeds. Cloning efficiencies were slightly higher for Tetir × ILL323 (83%) compared to Alpo × L. odemensis (67%). A total of 982 F₂ seeds were produced in the experiment with Alpo × L. odemensis, consisting of the 334 F₂ seeds of the original hybrid and 648 F₂ seeds produced by the 12 plants cloned; consequently, F₂ seed production was increased three-fold over the original hybrid (194%). A total of 6050 F₂ seeds were produced in the experiment with Tetir × ILL 323, made up of the 483 F₂ seeds of the original hybrid and 5567 F₂ seeds produced by the 15 plants cloned; therefore, F₂ seed production was increased by more than twelve-fold over the original hybrid (1153%). In both hybrids the F₂ seed production of cloned plants diminished in the three consecutive multiplication cycles, with the plants having experienced less vegetative development. In lentil, F₂ seed production of cloned plants is related for the first time to the length of their period of vegetative development. In conclusion, micropropagation of hybrids is an interesting tool to construct from a single individual large F₁ populations that enable to increase by a manifold the production of F₂ seeds useful for genetic studies and breeding.     

Genetic analysis of quantitative traits across environments in linseed (Linum usitatissimum L.)

Summary Fourteen lines of linseed (Linum usitatissimum L.) were evaluated for general and specific combining ability through line × tester cross analysis using five diverse testers in two different environments. Seventy F₁'s and nineteen parental genotypes were raised in completely randomized block design with two replications with respect to yield and yield related traits. Considerable genetic variation was observed for all the traits studied. The additive as well as non-additive gene effects played significant role in the inheritance of yield and related traits with preponderance of non-additive gene effects for all the traits studied. Higher proportion of general combining ability × environment interaction variance as compared to specific combining ability × environment estimates was recorded. Additive genetic variances were more sensitive than non-additive genetic variances to the changing environment. Low estimates of heritability (narrow sense) for primary branches per plant, capsules per plant, seeds per capsule, seed yield per plant, harvest index and oil content and medium heritability for days to 50% flowering, days to maturity, plant height and 1000-seed weight was observed. Among the female parents LCK-9816, Parvati, Himalini, KL-168 were good general combiners for yield and related traits along with oil content, whereas among male parents, Surbhi and KL-224 were good general combiners for yield related traits and oil content but KL-221 was good general combiner for seed yield and related traits.     

Sexual Transmission of Somatic Embryogenesis in Dactylis glomerate*

A Dactylis glomerata L. genotype that produces somatic embryos in vitro was tested for the ability to sexually transmit the embryogenic trait. Reciprocal crosses were performed between the embryogenic and two non-embryogenic genotypes. Leaf segments from 69 F₁ plants were cultured on Schenk and Hildebrandt medium amended with 30 μM 3,6-dichloro-o-anisic acid (dicamba). Somatic embryogenesis was expressed in 39 of the F₁ plants. The embryogenic parent was female for 18 of these plants and male for the other 21. The 39:30 ratio of embryogenic: non-embryogenic fits an expected 1:1 for tetrasomic inheritance of a dominant nuclear gene.     

Inheritance of black testa colour in lentil (Lens culinaris Medik.)

The inheritance of testa (seed coat) colour and interaction of cotyledon and testa colours were studied in seven crosses of lentil (Lens culinaris Medik.) involving parents with black, brown, tan or green testa and with orange, yellow or dark green cotyledons. Analysis of F₂ and F₃ seed harvested from F₁ and F₂ plants, respectively, revealed that although black testa is dominant over nonblack testa, its penetrance is not complete since both F₁ plants and heterozygous F₂ plants produced varying proportions of seeds with either black or nonblack testa. The F₂ populations of the crosses between parents with brown and tan, as well as brown and green, testa segregated in the ratio of 3 brown : 1 tan and 3 brown : 1 green, respectively, indicating monogenic dominance of brown testa colour over tan or green. The expression of testa colour was influenced by cotyledon colour when parents with brown or green testa are crossed with those having orange or green cotyledons. Thus F₂ seeds from these crosses with a green testa always had green cotyledons and never orange cotyledons. F₂ seeds from these crosses with a brown testa always had orange cotyledons and never green cotyledons. These results suggest diffusion of a soluble pigment from the cotyledons to the testa. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects of Wheat Chromosome 1D Telosomes on Hybrid Seed Development in Wheat × Rye Crosses

Pollination of ‘Chinese Spring,’ monosome 1D plants with rye results in failure of hybrid seed development in a proportion of the F₁ seeds corresponding to the transmission rate of the nullisomic 1D egg cells. Development and viability of these hybrid seeds closely resemble that normally observed in T. aurum× rye crosses. Using ‘Chinese Spring’ chromosome ID telosomic plants in crosses with rye, it was possible to illustrate that the observed effect was associated with the long arm of this chromosome.     

果实成熟度与后熟对樱桃番茄制种的影响

摘要：为了提高樱桃番茄采种产量和质量,降低杂交一代种子的生产成本。以不同成熟度果实直接剖果取种和其后熟处理收获的F1种子作为试验材料,研究了不同果实成熟度和后熟处理对樱桃番茄制种产量和质量的影响。结果表明：杂交种果半熟期采后经室内后熟至完熟的处理最佳。种子千粒重、活力和对后代生长发育的影响与完熟期采果制种的质量相当,而制种产量提高了12.1%。     

种子引发对水分胁迫下水稻发芽及幼苗生理性状的影响

不同基因型稻种经水引发及聚乙二醇(PEG)渗透胁迫引发处理均能降低稻种丙二醛(MDA)含量,促进可溶性总糖(SS)降解,加快稻种内部糖代谢进程,提高相溶性溶质脯氨酸(Pro)及可溶性蛋白质(SP)含量,也有利于提高苯丙氨酸解氨酶(PAL)、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,引发效果较明显。且适度PEG引发稻种的效果明显好于水引发,杂交籼稻在PEG浓度为20%的条件下引发效果最优,而常规粳型水稻在PEG浓度为10%~15%的引发条件下效果较好,但超出最高PEG引发浓度的阈值,会对稻种产生危害,影响其正常萌发。引发处理后的稻种对不同程度水分胁迫程度的响应表明,适当强度的引发处理利于激发稻种物质代谢、利于各水稻品种的萌发、幼苗形态指标及保护性酶等生理指标的显著提高,而严重的水分胁迫均不利于稻种萌发;表明引发处理虽能提高水分胁迫条件下种子活力,但稻种激发自身对外界萌发环境的协调能力有限,且不同品种间存在明显差异,籼稻优于粳稻。     

多种环境下大豆单株粒重QTL的定位与互作分析

定位大豆单株粒重QTL、分析QTL间的上位效应及QTL与环境互作效应, 有利于大豆单株粒重遗传机理的深入研究。利用147个F_2:14~F_2:18 RIL群体, 5年2点多环境下以CIM和MIM方法同时定位大豆单株粒重QTL, 检测到17个控制单株粒重的QTL, 分别位于D1a、B1、B2、C2、F、G和A1连锁群上, 贡献率为6.0%~47.9%;用2种方法同时检测到3个QTL, 即qSWPP-DIa-3、qSWPP-F-1和qSWPP-D1a-5, 贡献率为6.3%~38.3%;2年以上同时检测到4个QTL, 即qSWPP-DIa-1、qSWPP-DIa-2、qSWPP-B1-1和qSWPP-G-1, 贡献率为8.1%~47.9%;利用QTLMapper分析QE互作效应和QTL间上位效应, 7种环境下的数据联合分析得到1个QE互作QTL和4对上位效应QTL, 贡献率和加性效应都较小。在分子标记辅助育种中应该同时考虑主效QTL及各微效QTL之间的互作。     

Selection for Seed Yield in Lolium perenne L.*

Components of seed yield were estimated for each set of 100 plants derived from six varieties of Lolium perenne. Significant differences between the varieties were found for all components of seed yield, but the range was broader within each variety. An indirect selection of seed yield using the character seeds per spike produced a selection response similar to that obtained by direct selection on high seed yield per plant. A direct and indirect selection of characters estimated in small, drilled plots of topcross off-springs (F₁) was less successful than the selection based on the single plants. Spearman rank correlation coefficients between the single plants and their offsprings did not show significant agreement for seed yield. But altogether the results indicated that the increase of seed yield/area was about 6 % when 10 % of the best plants were selected.     

Male sterility in alloplasmic Brassica rapa L. carrying Eruca sativa cytoplasm

For the development of a new cytoplasmic male sterility (CMS) system in Brassica rapa (2n= 20, AA), intergeneric hybridization was performed in Eruca sativa (2n= 22, EE)×B. rapa. The original amphihaploid F₁ plant (2n= 21, EA) generated via embryo rescue produced a sesquidiploid F₁ plant (2n= 31, EAA), from which the alloplasmic F₃ plants were generated. In F₃, some progenies with malformed anthers were maintained as male-sterile lines up to the F5 generation. In the F₆ and F₇ generations, the alloplasmic male-sterile plants were bred by backcrossing to several B. rapa genotypes and were then classified into the three distinctive types: petaloid, antherless and brown anther, in addition to three intermediate types between them. By southern blot analysis, each plant of the petaloid and antherless types was shown to carry the cytoplasm genome of E. sativa. These male-sterile plants produced as many viable seeds as the corresponding male-fertile plants, although their nectary gland development was minimal. Consequently, CMS lines of the petaloid and antherless types with enhanced seed fertility and nectary gland development could provide promising plant materials for F₁ seed production in B. rapa.     

添加蚓粪和蛭石对菇渣培育番茄幼苗生长的影响

摘要：[方法]采用菇渣为原料,在菇渣中加入蚓粪和蛭石,复配成育苗基质。菇渣与蛭石按8：1和4：1体积比混合的基质培育的番茄幼苗的根鲜重、根干重和为育苗基质培育番茄幼苗,[目的]研究其对番茄幼苗的生长影响特征。[结果]结果表明,相比市售基质,菇渣复配育苗基质能够明显提高番茄幼苗叶片叶绿素含量。菇渣与蚓粪、蛭石按8:1:1体比混合的育苗基质培育的番茄幼苗在茎粗、根长、根表面积、根体壮苗指数都大于市售基质。菇渣加入蚓粪、蛭石复配基质的各处理的番茄幼苗茎叶鲜重、茎叶干重、总鲜重、总干重和根冠比与市售基质相比差异不显著。[结论]总之,菇渣可以作为基质材料培育番茄幼苗,添加蚓粪和蛭石都有利于提高番茄幼苗的壮苗指数。本实验条件下,推荐采用菇渣与蛭石按照8～4：1体积比复配的基质进行番茄育苗。     

Combining ability of seed vigor and seed yield in soybean

Studies have shown no consensus in relationships between seed yield and vigor in soybean [Glycine max (L.) Merrill]. The lack of information regarding the inheritance of seed vigor prompted this study to determine the types of gene action and combining ability estimates for seed vigor and its related traits. Five high and six low seed vigor soybean genotypes were crossed in a diallel, and selfed to produce 55 F₂ progenies, which were examined, along with the parents, for seed vigor, yield, and seed weight. Significant genotype and environment effects were found for seed vigor and yield. General combining ability (GCA) effects for seed vigor and seed yield were significant (p≤ 0.01) and larger than specific combining ability (SCA) effects. Significant GCA and SCA effects were found for seed weight, indicating that both additive and non additive genetic effects were involved in conditioning seed weight. The ratios of mean square, 2GCA / (2GCA+SCA), were 0.96 for seed vigor and 0.93 for seed yield. These ratios indicated that additive gene effects were more important than non additive gene effects for seed vigor and seed yield in these crosses. Mean seed vigor(83.8%), as determined by accelerated aging germination, and mean seed yield (2,155 kg ha^-1)in high vigor × high vigor crosses were higher than the high vigor × low vigor and low vigor × low vigor crosses. Mean percent accelerated aging germination rates in F₂ populations from diallel crosses were significantly related to mid-parent seed vigor(r² = 0.52^**) and midparent seed size (r² = 0.31^**). These results indicated that levels of seed vigor can be improved through breeding, while maintaining high yields because of the predominance of GCA effects in both seed vigor and seed yield. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic analysis of male sterility in rice mutants with environmentally influenced levels of fertility

Summary Twenty-six male sterile plants grown in the field were recovered in the M7 generation from ethyl methane sulfonate-treated material of the rice cultivar M-201. Fertility increased five-fold when ratooned plants from the field were grown in a growth chamber with a 12 hour daylength. Crosses between mutant and normal fertile cultivars produced fertile F₁ plants. Female fertility was normal as judged by percent seed set from unbagged panicles of parental and recombinant lines. Transgressive segregation for fertility was observed for all crosses in the F₂ and F₃ generations. Five of 37 F₃ male sterile plants showed moderate levels of seed fertility under winter greenhouse conditions and reduced seed set when transplanted to summer field plots. Fertility data from reciprocal crosses suggested cytoplasmic factors had little or no effect on levels of male sterility in the mutant lines. Chi-squared analyses of F₂ and F₃ generation results indicated male sterility of the mutants is conditioned by two nuclear genes with epistatic effects.     

冬小麦种子的发育及其田间活力

１９９３－１９９４年北京对六冬小麦品种籽粒发育程度及不同发育程度籽粒的发芽力、活力进行了研究。从花后５天开始每３天取样一次,测定籽粒的干重,观察了其中两种材料发育早期籽粒种胚的器官分化,对各发育程度种子进行了标准发芽测定及田间幼苗活力鉴定。