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31.
Diploid families of Tuberosum hybrids as well as Tuberosum-wild species F1 hybrids were generated to select 2n-egg producing genotypes of different genetic backgrounds. Plants were selected if they
produced more than four seeds per berry after pollination with tetraploid males (2x⋅ot4x-crosses). From the nine families
of Tuberosum hybrids that were derived from one or two 2n-egg producing parents, 12 out of 82 (15%) 2n-egg producing plants
were selected. From the 32 families of Tuberosum-wild species F1 hybrids, 21 of 274 (8%) 2n-egg producing plants were selected. The level of 2n-egg formation was estimated in 25 selected
diploid hybrids and five control clones (three high, one moderate and one low 2n-egg producers) on the basis of seed set following
2x⋅4x-crosses using 13 tetraploid males in four crossing years. Besides the effect of the diploid 2n-egg producing female
on the seed set following 2x⋅4x-crosses (P = 0.0001), there was a significant effect of the tetraploid male (P = 0.0001),
whereas the effect of the crossing year (P = 0.0688) was less significant. On the basis of differences in the seed set following
2x⋅4x-crosses as compared to the control clones for low, moderate and high level of 2n-egg formation, the level of 2n-egg
formation in two of the newly selected hybrids was classified as very high, four were high, sixteen were moderate and three
were low. The significance of the selected hybrids for the genetic analysis of various restitution mechanisms of 2n-egg formation
is discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Lokesh Bora Rangasamy Muthusamy Vijayakumar Mathian Ganga Narayanapillai Meenakshi Ganesan Mangaldeep Sarkar Manoj Kundu 《Plant Breeding》2023,142(1):118-127
Polyploid breeding is an effective tool to induce variability in the existing population, specifically in the crops having very narrow genetic base such as acid lime. Hence, an experiment was conducted to induce polyploidy in acid lime through colchicine treatment. Higher frequency of triploids were obtained in 250 μM colchicine treatment (27.27%), whereas combination of 3× (21.42%), 4× (13.33%) and aneuploid (6.67%) were induced at 500 μM colchicine treatment. Measurement of stomatal density and guard cell size of colchiploids revealed that the former one has negative relation with ploidy level and a positive relation was observed between guard cell size and ploidy level. Further, area and size of nuclei also had a positive relation with ploidy level. Hence, stomatal density, guard cell and nuclei size can be used effectively as morphological marker for preliminary polyploid screening. From the experiment, it can be concluded that 500 μM colchicine treatment of in vitro derived shoot tip explants of acid lime is optimum for creating maximum possible variability through polyploidization in the existing acid lime population. 相似文献
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‘寒富’苹果与其同源四倍体耐盐差异研究 总被引：2，自引：0，他引：2
以含有200 mmol·L-1 NaCl的1/2 Hoagland营养液处理‘寒富’二倍体苹果及其同源四倍体幼苗8 d,分别在处理0、2、4、6和8 d时进行叶片相关生理指标及水通道蛋白相关基因表达水平的测定,比较分析两者的耐盐性差异。结果表明:盐胁迫下四倍体的形态表现优于二倍体;四倍体和二倍体的叶片相对含水量一直在下降,二倍体下降幅度大于四倍体,丙二醛含量和脯氨酸的积累随胁迫时间的延长而增加,二倍体含量始终高于四倍体;NaCl处理8 d时,二倍体的叶片相对含水量比四倍体低8%,丙二醛含量比四倍体多4.466 nmol·g-1FW,脯氨酸含量为四倍体的1.18倍;盐胁迫下两者叶片中水通道相关蛋白基因Md PIP1;1、Md PIP2;1、Md TIP1;1和Md TIP2;1的表达量均出现先下降后上升趋势,且四倍体均高于二倍体,尤其在处理24 h时差异最显著。四倍体比二倍体具有更强的耐盐性,可能与盐胁迫下四倍体相关水通道蛋白基因表达水平较高有关。 相似文献
35.
Solanum spegazzinii Bitt., a wild diploid potato species endemic to Argentina, possesses resistance to adverse biotic and
abiotic agents. Northwestern Argentinean populations grouped according to their morphological variability (G1 = localities
East of the Calchaquí Valley, G2 = Calchaquí Valley and G3 = locality Belén) presented problems in seed set following controlled
crosses. Thus, to evaluate if the morphological variability previously reported was sustained on a genetic basis, three introductions
per group and five plants per introduction were used in controlled crosses (genotypic combinations). These were classified
according to the number of seeds produced per fruit. Pollen-style compatibility relations were studied in those crosses that
did not set seeds or that produced less than 30 seeds each. Within groups, G1 produced seeds normally, whereas hybridization
barriers were found in 71.4% and 50.0% of the combinations within G2 and G3, respectively; on the other hand, from 46.7% to
73.3% of the combinations among groups exhibited similar barriers. Variability in the expression of the sites of pollen tube
inhibition in the style was observed both within and among groups. Speculations are made on the possible hybrid origin of
the populations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Effect of high temperature on the production of 2n pollen grains in diploid roses and obtaining tetraploids via unilateral polyploidization 
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下载免费PDF全文 Laurent Crespel Camille Le Bras Daniel Relion Hanaé Roman Philippe Morel 《Plant Breeding》2015,134(3):356-364
To integrate the gene pool of a wild species (primarily diploid) into a cultivated pool (primarily tetraploid), a crossing between a dihaploid cultivated rose and a hybrid of Rosa wichurana allowed to obtain interspecific diploid hybrids that produced 2n pollen grains. A return to a tetraploid level sought by breeders can then be considered using sexual polyploidization, obtained by crossing a tetraploid cultivated rose with these hybrids. Application of a high‐temperature regime led to a small but significant increase in the percentage of 2n pollen grains in these hybrids of up to 4.6%. This result was obtained by applying high temperatures close to 32°C during the day to plants cultivated in a glasshouse during recurrent cycles of bloom. Crosses were made between an unreleased tetraploid hybrid tea rose, as a female, and the diploid hybrid that produces the most 2n pollen grains. Tetraploid (42.1%) and triploid (57.9%) offspring were obtained. The use of these 2n pollen grains of the first division restitution type should facilitate the introgression of complex traits of interest. 相似文献
38.
Summary Plants of Lolium perenne, L. multiflorum and L. hybridum (331, 51 and 18, respectively) were screened for 2n pollen production. The screening was based on the size differences that are expected to be found between n and 2n pollen of a plant. It was found that 28 plants of perennial ryegrass-belonging to 13 cultivars-produced produced pollen grains of heterogenous size (big and small). The estimated frequency of big pollen grain production was higher than 10% in ten out of 28 plants and in three of them it reached a value of 100%. Eight plants obtained from two 4x × 2x crosses, in which the male parent had been previously identified as producing pollen grains of heterogenous size, was tetraploid. The cytological mechanism of big pollen grain formation observed in three plants consists in the lack of spindle formation and, consequently, of chromosome migration in anaphase II. From these breeding and cytological results, it was concluded that the big pollen grains observed were viable 2n pollen grains. The nuclei of the 2n pollen grains produced by this mechanism are genetically equivalent to those formed by the restitution of the second meiotic division. The value of these gametophytes in a breeding program of Lolium is discussed. 相似文献
39.
Summary The extent and pattern of polyploidy in the tuber-bearing Solanums varies among the many taxanomic series that have been identified in this subsection of Solanum. While several series appear to be entirely diploid, others exhibit a range of ploidy levels from 2x to 6x, and some contain only polyploid species.In many diploid, triploid and tetraploid species 2n gametes (gametes or gametophytes with the sporophytic chromosome number) have been detected. Both 2n eggs and 2n pollen occur. 2n gametes provide the opportunity for unilateral and bilateral sexual polyploidization. The genetic determination and consequences of sexual polyploidization strongly suggest that 2n gametes have been the major instrument in the polyploid evolution of the tuber-bearing Solanums. Somatic doubling of species and interspecific hybrids appears to be of very limited importance.New evidence for the occurrence of 2n eggs and 2n pollen in many species is reported, and data from the literature are added to illustrate the widespread distribution of 2n gametes throughout the subsection. A very high correlation is found between polyploidy and 2n gametes, and its significance is discussed. Proof is presented for the occurrence of alleles governing 2n pollen production in the cultivated tetraploids, providing additional evidence for the hypothesis that 2n gametes have been involved in their origin.Multiple unilateral and bilateral sexual polyploidizations are proposed for the origin of the cultivated tetraploids: this accounts for the large variability encountered in this group, which closely resembles that of the related diploids. Similar evolutionary pathways are hypothesized for the other polyploid complexes in the subsection.A scheme is proposed in which participation of both 2n and n gametes link together all ploidy levels in the tuber-bearing Solanums, thus overcoming the ploidy barriers and providing for gene flow throughout the sympatric species of the subsection.Paper No. 2093 from the Laboratory of Genetics. Research supported by the College of Agricultural and Life Sciences, a gift from Frito-Lay, Inc., and grants from NIH (GM 15422) and The International Potato Center. Plant materials, unpublished chromosome counts and technical help of IR-1 are gratefully acknowledged. 相似文献
40.
Summary New haploid-wild species hybrids (H-S) with desirable tuber type and 2n gamete production have been identified. They provide the opportunity for the production of inexpensive, 4x hybrid TPS from 2x×2x crosses. A proposed system to utilize plants producing either 2n eggs or 2n pollen is described. One H-S hybrid (female parent) would be selected for male fertility, self-incompatibility, high frequency of 2n eggs and no 2n pollen; an unrelated H-S (male parent) for male fertility and high 2n pollen production. In addition both parents would be selected for profuse flowering, attractiveness to bumblebees and other desirable characteristics. The male and female parents would be planted in alternate hills with bumblebees doing the pollinations. The elimination of emasculation, pollen collection, and hand pollination could reduce 4x hybrid TPS costs by more than 50 percent. 相似文献