UseoftheEndospermBalanceNumber(EBN)inPotatoGeneticsandBreeding

在马铃薯初花期喷施植物生长调节剂多效唑,试验结果表明:多效唑显著抑制植株的高度,单株结薯数下降,大薯率上升,当每667m2喷施多效唑75g,浓度在2.5g.L-1时是本试验中提高产量的最佳浓度,干物质和淀粉均有明显的提高。说明喷施多效唑具有控上促下的作用,从而有利于提高产量和品质。     

多效唑对金柿产量及生长发育的影响

【目的】探讨柿树矮化密植、早果丰产技术。【方法】于柿树生长期喷施不同浓度的多效唑（pp333）,分析多效唑对金柿产量及生长发育的影响。【结果】叶面喷施多效唑对金柿平均单株产量、坐果率、果枝率、成枝率均有显著影响。多效唑可极显著地抑制其营养生长,促进坐果,提高产量。其中以800mg／kg处理浓度效果最佳。【结论】喷施浓度800mg／kg多效唑可以有效抑制金柿营养生长,提高产量。     

不同剂量多效唑拌种对大麦品种单二产量及构成要素的影响

采用单因素随机区组排列设计,研究了不同多效唑用量拌种对单二主要农艺性状和产量的影响,同时研究了在拔节期喷施40g／667m^2多效唑对单二主要农艺性状和产量的影响。结果表明,随着多效唑用量的增加,株高呈降低趋势,多效唑能够较好地降低株高,防止大麦倒伏,起到保产、稳产的作用;在拔节期喷施40g／667m^2多效唑较单纯拌种能显著提高产量;用0．05g和0．15g多效唑对75g单二拌种并在拔节期喷施多效唑40g／667m^2时,单二产量较空白对照增产显著。     

15%多效唑可湿性粉剂对水稻生长、产量及品质的影响

通过对水稻生长指标、产量和品质的分析,了解15%多效唑可湿性粉剂对水稻的影响,为生产实践提供理论依据。2012和2013年,用不同浓度的15%多效唑可湿性粉剂在水稻一叶一心期对其进行喷施处理,收获前记录数据并分析。结果发现：不同浓度的15%多效唑可湿性粉剂对秧苗的抑制率为5.92%～16.85%,水稻分蘖率和实际产量增加分别为37.04%～70.37%和5.82%～16.62%。说明多效唑可湿性粉剂对水稻的生长发育有明显的调节作用,能够显著地抑制稻株的生长、促进分蘖和提高产量;15%多效唑可湿性粉剂对水稻品质有所改善,但效果不显著。     

南方旱地多熟间套作马铃薯喷施多效唑的增产效果试验

试验结果表明:马铃薯喷施多效唑后有抑制地上部生长,促进植株粗壮和提高产量的作用。其适宜浓度应控制在75￣125mg.L-1之间,同时有利于旱地多熟套种后熟作物的生产。说明这是一条实现旱地全年多熟高产增收的重要技术措施之一。     

多效唑对鄂马铃薯5号产质量的影响

[目的]探索不同浓度多效唑对马铃薯产质量的影响。[方法]在马铃薯现蕾期,设置300、350、400、450 mg/L的15%多效唑溶液喷施,探索不同浓度多效唑对马铃薯产质量的影响。[结果]结果表明,喷施多效唑400 mg/L的15%多效唑溶液675 kg/hm2的处理效果最好,产量达到33 060.9 kg/hm2,比对照增加14.21%。[结论]在马铃薯上施用浓度为400 mg/L的15%多效唑溶液,用量为675kg/hm2为宜。     

不同浓度多效唑对大麦生长和产量的影响

以保大麦8号为试验材料,研究喷施不同浓度多效唑对大麦生长和产量的影响。结果表明,通过喷施15%多效唑可湿性粉剂,大麦株高、倒伏率、千粒质量降低,有效穗、产量增加。其中,喷施多效唑1 000倍液对降低大麦株高效果最佳(P0.05);喷施多效唑500倍液对降低大麦倒伏率、增加产量效果显著(P0.05)。     

多效唑对麦茬旱稻农艺性状影响及生理作用的研究

以早稻277为材料．在l叶l心期进行了不同浓度多效唑喷施试验。麦茬早稻苗期喷洒多效唑对植株高度有明显的降低作用．可提高秧苗素质和抗倒力。同对照相比．叶面喷施多效唑可使麦茬早稻产量增加10％左右。增产的生理作用主要表现在光合速率提高，气孔导度和蒸腾速率提高。叶面喷施多效唑可增加麦茬早稻的穗粒数。     

马铃薯叶面喷施植物生长调节剂对植株和产量的影响

通过对马铃薯叶面喷施不同浓度植物生长调节剂(多效唑)和微量元素,研究不同浓度多效唑和微量元素配合喷施对马铃薯叶绿素含量、光合速率、淀粉含量、产量等的影响。结果表明,不同浓度多效唑和微量元素配合使用,可使马铃薯顶端生长受到明显抑制,茎粗增加,叶绿素含量增加,光合速率增加到一定程度有所下降。淀粉含量随着浓度增加而增加,到一定程度也有下降的趋势。     

多效唑对大豆不同叶型近等位基因系产量和品质的影响

在大田条件下,以2对不同叶型近等位基因系大豆品系A31和6059为材料,于始花期叶面喷施不同浓度的多效唑来研究不同叶型大豆品系对多效唑的反应.结果表明:始花期叶面喷施不同浓度的多效唑对大豆有显著的增产作用,同时还改善了叶片的生理功能和产量性状.此外,籽粒蛋白质含量得到了提高,脂肪含量降低.不同叶型品系对多效唑的反应不同,表现为圆叶品系的增产效果好于尖叶品系.     

The reproductive biology of the potato and its implication for breeding

Summary Haploidy, 2n gametes, synaptic mutants, stylar barriers, endosperm barriers. Endosperm Balance Number (EBN) and its relationship to 2n gametes, stylar barriers and disomic genetics are a part of the reproductive biology of potato. Also all are tools for isolation and preservation of a species identity. Haploidy and 2n gametes allow for interploidy gene transfer. Parallel spindles and synaptic mutants permit the transfer of entire parental genomes intact and are powerful tools in potato breeding. Stylar barriers provide a mechanism for interspecific isolation via unilateral incompatibility. Incongruity has also been invoked. Endosperm barriers have been discussed in terms of EBN which requires a 2 maternal:1 paternal ratio in the endosperm for successful seed development. Genetic models suggesting three unlinked genes in a threshold-like system and a two gene system have been proposed. A relationship may exist between EBN and stylar barriers. The use and manipulation of 2n gametes, stylar barriers and EBN have been used effectively in germplasm transfer from species to cultivated potato. Note: This paper is dedicated to Dr S.J. Peloquin, Emeritus Professor, Department of Horticulture, University of Wisconsin-Madison, a mentor, friend and colleague, in recognition of the enormous contributions he has made to this area and for his enthusiasm for and stimulation of others to an awareness of the importance of its application to plant improvement. Cooperative investigation of the Vegetable Crops Research Unit, United States Department of Agriculture, Agricultural Research Service and the Wisconsin Agricultural Experiment Station.     

Interspecific crossability and cytogenetic analysis of sexual progenies of Mexican wild diploid 1EBN speciesSolanum pinnatisectum andS. cardiophyllum

Mexican wild diploid species,Solanum pinnatisectum (S. pnt) (2n=2x=24, 1EBN: endosperm balance number) is a useful germplasm source of late blight and Colorado potato beetle (CPB) resistance in potato improvement. However, it is very difficult to cross this species with other 1EBNSolanum species. Sexual hybrids among three accessions ofS. pnt and two accessions ofS. cardiophyllum (S. cph) (2n=2x=24, 1EBN) were studied. There were large differences in the cross-compatibility among the genotypes and accessions from these two 2x-1EBN species. Interspecific incompatibility existed in the crosses betweenS. pnt andS. cph, in whichS. cph functioned only as the male parent. The crosses with accessions PI 275236 ofS. pnt produced 35 hybrids following the conventional propagation procedures. Seven hybrids were obtained with theS. pnt accession PI 275233 with the aid of embryo rescue, while hybridization involving accession PI 253214 resulted in no fruit. The cytogenetic analysis indicated that all of the hybrids derived from crosses of accession PI 275233 ofS. pnt withS. cph had 2n = 24 chromosomes and were pollen fertile. Crosses involving accession PI 275236 ofS. pnt produced both 2x (2n=24) and 3x (2n=36) hybrids. Meiotic analysis at metaphase I of pollen mother cells (PMCs) showed a fairly high rate of chromosome pairing that averaged between 10.10 and 11.10 bivalents per cell in most of the 2x hybrids, indicatingS. pnt andS. cph have the similar genome. A high frequency of trivalents and quadrivalents were observed in 3x hybrids derived fromS. pnt 2 ×S. cph 1, indicating homology exists among these chromosomes. These results suggest that specific gene(s) and not either differences between genomes or EBN controlled interspecific crossability and embryo development. The disease and insect tests on the 2x and 3x hybrids revealed that all have high levels of resistance to both late blight and CPB. Thus it could appear that selection of genotypes is a key for successful interspecific hybridization when using Mexican wild diploid species as a source of economic important traits.     

Chromosome Number Manipulation as Part of Potato Pre-breeding Programs

The cultivated potato(Solanum tuberosum L.) is a tetraploid(2n=4x=48) and can be improved with the incorporation of desirable traits from other Solanum species.Often the transfer of these traits is hindered by complex genetics and breeding barriers within potato.Parthenogenesis and microsporogenesis are used in chromosome number manipulation allowing breeders to reduce the potato's chromosome number to dihaploid(2n=2x=24)[diploid] or monohaploid(2n=x=12) from which a predictable transfer of traits can be made,in accordance with the endosperm balance number theory(EBN).Furthermore,the reproductive processes of first division restitution(FDR) and second division restitution(SDR) are utilized in order to increase the chromosome number for incorporation into the cultivated potato.     

Introgression of cold (4 C) chipping from 2x (2 endosperm balance number) potato species into 4x(4EBN) cultivated potato using sexual polyploidization

Cold-chipping cultivars could reduce microbial spoilage and chemical use due to cold storage of chipping potatoes. Sexual polyploidization breeding schemes that introgress cold chipping from diploid potato species may develop improved cultivars at an accelerated rate. The research objectives were (1) to determine the breeding behavior of cold chipping introgressed from 2× 2 Endosperm Balance Number (EBN) potato species into 4×(4EBN) progeny using sexual polyploidization, and (2) to determine if differences exist between 2n gametes and n tetrasomic gametes for transmission of cold chipping. Experimental families of 4×(4EBN) progeny were synthesized using sexual polyploidization (2× × 4× and 4× × 2×) and 4× × 4× matings using cold-chippingS. phureja and cultivated potato -wild species (C -W) hybrid parents. Control families from 4× × 4× matings using as parents current industry leading germplasm were also made. Progeny were field grown and evaluated for chip color (1 light-10 dark, ≤4.0 is industry acceptable) after 3 and 6 months storage at 4 C. A larger percentage of progeny from experimental families had acceptable chip color compared to control families, likely due to introgression of cold-chipping alleles from diploid potato species. Out of experimental families, the best chip color means, highest phenotypic variance, and greatest percentage of acceptable chipping progeny resulted in 2× × 4× and 4× × 2× matings. The ability of 2n gametes to transmit dominant alleles to high frequencies of 4× progeny may contribute to the superiority of 4× -2× crosses. Breeding schemes that use sexual polyploidization in conjunction with early generation selection should rapidly develop 4× cold-chipping germplasm.     

Haploid induction in Mexican polyploid species and colchicine-doubled derivatives

Haploids (tetraploids and triploids) were obtained from crosses between colchicine-doubled octaploid and natural hexaploid Mexican potato species and the Gp. Phureja clone 1.22 as the pollinator, but none were obtained from crosses of natural 4x(2EBN) Mexican species with 2x(1EBN) pollinators. The manipulation of ploidy and Endosperm Balance Number (EBN) of tetraploid Mexican potato species was useful in explaining the occurrence of pseudogamous parthenogenetic haploid production. The pollinator effect, EBN, and maternal influence are important characters to consider in searching for haploid-inducing pollinators among 2x(2EBN) as well as 2x(1EBN) potato species.     

Variation for 2n pollen production and male fertility in wildSolanum germplasm resistant toPhytophthora infestans (Mont.) de Bary (US-8)

Wild potato species possess genetic variability for valuable traits including resistance toPhytophthora infestans, the causal agent for potato late blight disease. Breeding schemes using 2n gametes are a powerful tool for introgressing these traits. Forty-five plant introductions (PIs) across 12Solanum species representing various Endosperm Balance Numbers (EBN) and having resistance toP. infestans (US-8, isolate ND 95-2) were screened for 2n pollen production and male fertility. Species evaluated were 2x(lEBN)S. bulbocastanum, S. cardiophyllum, S. pinnatisectum, andS. trifidum; 2x(2EBN)S. berthaultii, S. megistacrolobum, S. microdontum, andS. verrucosum; 4x(2EBN)S. fendleri andS. stoloniferum; 6x(4EBN)S. guerreroense; and 2x(unknown EBN)S. polyadenium. Acetocarmine staining and cytological analyses were used to determine 2n pollen production and pollen stainability from genotypes grown across three locations. Based on frequency, genotypes were assigned to 2n pollen production categories (0≤1%, Low=1%–10%, Medium=11%–60%, and High≥60%) and pollen stainability categories (0≤1%, 1=196–5%, 2=6%–10%, 3=11%–20%, 4=21%–50%, and 5≥50%). Eleven of the 12 species and 37 of the 45 PIs examined contained genotypes producing ≥1% 2n pollen with ranges of 0%–63.6% and 0%–81.8%, respectively. Dependence was found between location and pollen stainability, EBN and pollen stainability, but not for location and frequency of genotypes with 2n pollen. Stability for 2n pollen production was observed across environments. Among the 1EBN germplasm, dependence was found between 2n pollen and pollen stainability. Resistance toP. infestans was found to be independent of 2n pollen production; therefore, identifying genotypes combining 2n pollen production, fertility, and resistance toP. infestans was possible.     

Haploids of tetraploid (2n=4x=48) Mexican potato species—Their extraction,cytology and crossability

Successful isolation of haploids (2n=2x=24) from 4x(2EBN) Mexican species was achieved by using Modified Wenzel (MW) and Nitsch and Nitsch (NN) media for anther culture. Both media, MW and NN, gave consistent regeneration of plantlets from 4x(2EBN) Mexican species, and responses to the media were both species and accession (PI) specific. Plantlets regenerated directly from microspores, by-passing the callus cycle, were mostly haploid (2n=2x=24). Haploid plants appeared smaller and weaker than their parents with a drastic reduction in both male and female fertility. Abnormalities observed during meiosis and the lack of success in crossing confirmed the effect of the meiotic irregularities observed in the haploids. A total of 290 seeds was obtained from the 4x × 2x crosses of 4x Mexican species with irradiated pollen of 2xS. cardiophyllum and 2xS. chancayense; however, no haploid (2n=2x=24) plants resulted. Extraction of haploids from colchicinedoubled 4x (2EBN) or natural 6x(4EBN) Mexican species using a Phureja pollinator was examined to provide clues to the potential of using 2x (1EBN) pollinators for haploid induction in 4x(2EBN) × 2x(1EBN) crosses.     

Germplasm transfer from the wild tetraploid speciesSolanum acaule bitt. to the cultivated potato,S. tuberosum L. using 2N eggs

Solanum acaule Bitt. (acl ¹, 2n=4x=48 and 2n=6x=72) is a wild potato species in which resistance to adverse biotic and abiotic agents has been found. The tetraploid subspeciesacaule andaemulans cannot be easily crossed with the common potato,S. tuberosum L. Grouptuberosum (tbr, 2n=4x=48) because the development of the endosperm in the hybrid seed is abnormal. Since 4xacl behaves as a diploid in intra and interploidy crosses, it was postulated that the hybridization barrier withtbr could be overcome if the wild species produced 2n gametes. One hundred and ninety-seven plants of 4xacl (22 introductions) were screened for pollen of heterogeneous size; only two plants produced this type of pollen, with 3% and 5% of pollen in the large class, respectively. On the other hand, 427 plants (47 introductions) were screened for 2n eggs through controlled crosses withtbr. Forty-one plants (13 introductions) produced 219 berries of which 46 contained at least one plump seed. Seed from berries with low seed set gave rise to hexaploid hybrids possibly through the functioning of 2n eggs from 4xacl. A sample of these hybrids was successfully backcrossed as female parents totbr, giving rise to 5x BC₁ progenies. These BC₁ progenies could be easily back-crossed totbr, yielding tetraploid or near tetraploid BC₂ plants.     

Male fertility and 2n pollen production in haploid-wild species hybrids

Hybrids (2n = 2x = 24) from crosses between Group Tuberosum haploids (2n = 2x = 24) and 24-chromosome, wild species must be fertile and produce 2n gametes if they are to be used in breeding schemes involving sexual polyploidization. Male fertility of the 2x hybrids depends primarily on the species parent. Hybrids involvingS. berthaultii, S. chacoense, S. kurtzianum, S. spegazzinii, andS. tarijense as parents are male fertile. The haploid parents are male sterile, so the species not only contribute genetic diversity and desirable traits, but also genes necessary for male fertility.S. infundibuliforme, S. raphanifolium, andS. sanctae-rosae parents produced male sterile hybrid progeny, while use ofS. boliviense, S. bukasovii, S. canasense, S. microdontum, andS. sparsipilum results in families containing both fertile and sterile plants. Sterility may be due to interactions between Tuberosum cytoplasm and dominant nuclear genes from the species. Genetic male sterility and environmental conditions may also be responsible for low pollen stainability in some hybrids. Many fertile, 2x hybrids produce 2n pollen. Selection for 2n pollen in the species is fast and efficient, but meiotic analysis is required in male sterile haploids. Fortunately, selection in the species parent alone results in a large number of 2n pollen-producing hybrids. These 2x hybrids have been used to generate tetraploids via 4x × 2x crosses.