Flowering behaviour,male sterility and berry setting in tetraploid Solanum tuberosum germplasm

Summary Six hundred and seventy six accessions of cultivated potato (Solanum tuberosum ssp. tuberosum) from 25 countries, were studied for flowering and fruiting behaviour under long days (12–14 h). Flowering intensity ranged from dropping of floral buds just after initiation to profuse blooming. The majority (58.3%) of the accessions bloomed profusely, though 20.4% of the accessions did not bloom at all. Weeks to flowering ranged from 6 to 15 and the majority (66.5%) of the flowering accessions bloomed within 8 to 9 weeks after planting. Duration of flowering ranged from 1 to 10 weeks and the majority (68.1%) of the flowering accessions bloomed for 1 to 4 weeks only. Twentythree per cent of the flowering accessions were completely male sterile. Maximum male fertility was 90% only. No berry setting was observed in 31.8% of the flowering accessions. Only 54.3 per cent of the accessions were found to be fertile in all respects and could be used both as male and female parents. Premature bud abscission was the major cause of sterility. Peru was the best source of profuse-flowering genotypes, Poland was the best source of early flowering genotypes and Mexico was the best source of long duration flowering and good berry setting genotypes. The results suggested that flower bud formation; the growth and development of mature flowers; weeks to flowering and duration of flowering are independent characters controlled by different genes of quantitative nature. Berry setting and duration of flowering were closely associated (r=0.95). Genetic as well as environmental factors interfered with the developmental process leading to flower production and berry setting at different times in different genotypes. The practical implications of these results for true potato seed production are discussed.Publication No. 1298, CPRI, Shimla.     

Identification of a Stable Maintainer Line for 'Polima' Cytoplasmic Male Sterility in Rapeseed (B. napus L.)

‘Polima’ cytoplasmic male sterility (CMS) was transferred to three different genotypes of B. napus i.e. GSL-1, ISN706 and HNS-8 by repeated backcrossing and was found to be completely stable in the nuclear background of synthetic B. napus genotype, ISN706, derived from a cross B. campestris ssp. oleifera var. brown sarson ×B. oleracea var. botrytis cv. Tusa Katki'. The BC₅ and BC₆ generation lines of ISN706, GSL-1 and HNS-8 with ‘Polima’ CMS were grown under a range of temperature and photo-period conditions to test their stability. No breakdown in sterility was observed in ‘Polima’ ISN706 and, therefore, this genotype can be used as a maintainer for hybrid seed production.     

对两个玉米雄性不育系的细胞质分类研究

本文从普通遗传学、植物病理学和分子生物学的水平对玉米雄花不育系—元徐cms—小黄和恩二激cms—大黄进行了综合性的分类研究。大田的育性反应表明，这两个不育系的育性恢复受一对显性基因控制。对花粉染色的观察发现F1可育花粉与败育花粉基本上呈1：1分离。用小斑病T小种接种，这两个不育系不表现专化感染。通过mtDNA的分析     

论光敏核不育系HN5s的分类地位

程氏指数法、外稃双峰乳突鉴定法、同工酶分析及亲和性分析等4种方法研究了光敏核不育系HN5s的分类地位.结果显示:HN5s在程氏指数、外稃双峰乳突鉴定均表现类似籼稻的特征,但脱粒性明显属粳型;除Amp外.同工酶Acp和Est也都呈籼稻的特征;亲和性研究表明,HN5s对4个广亲和性鉴定标准测验种和7个典型籼、粳品种均有较高的杂交亲和     

Development of TGMS lines for developing two-line rice hybrids for the tropics

A breeding program was initiated at the International Rice Research Institute (IRRI) in 1990 to develop thermosensitive genic male sterile (TGMS) rice lines for developing two-line rice hybrids for the tropics. The TGMS trait was transferred from a temperate japonica TGMS mutant, Norin PL 12, to indica and tropical japonica rice varieties using the pedigree selection procedure. Six new TGMS rice lines adapted to tropical conditions were developed which showed complete pollen and spikelet sterility when maximum temperature was higher than 30 ^°C 1–2 week after panicle initiation. However, up to 85.5% spikelet fertility was observed when these lines were exposed to 26–29 ^°C during the critical stage. Using two of these TGMS lines, some heterotic rice hybrids showing 1–1.6 t/ha higher grain yield than the inbred check varieties were identified in unreplicated observational yield trial conducted at IRRI. Two of the six two-line hybrids yielded significantly higher than the check variety in a replicated preliminary yield trial. This revised version was published online in July 2006 with corrections to the Cover Date.     

短光低温不育水稻新种质的花药培养研究

对短光低温不育水稻进行花药培养的结果表明：不同基因型材料的花培力差异较大；同一材料在不同的基本培养基和激素配比中进行培养的效果不同，对宜DIS，以M8附加2,4-D(2mg/L) NAA(2mg/L) Kt(1.5mg/L)的花培力最高；不同时间段所取的材料花培力差异较大，可能与材料生长所处的最适环境不同有关；适当的通气状况有利于绿苗分化率的提高。     

不同类型杜仲雄花茶活性成分的含量测定

采用紫外分光光度法和高效液相色谱法测定杜仲雄花茶中总黄酮、绿原酸及京尼平苷含量,探讨不同原料生产的杜仲雄花茶活性成分含量差异。结果表明,杜仲雄花茶中总黄酮、绿原酸及京尼平苷含量分别为1.89%～6.22%、0.06%～2.81%、0.06%～2.09%;不同类型杜仲雄花茶中各类活性成分含量有所差异,以花朵为原料生产的杜仲雄花茶中总黄酮含量和绿原酸含量均为最高,以花蕊为原料生产的杜仲雄花茶中京尼平苷含量最高,发酵杜仲雄花茶中各类活性成分含量均偏低。本研究可为开发不同保健功能杜仲雄花茶提供理论依据,有利于进一步推动杜仲雄花资源的开发利用。     

Moricandia arvensis cytoplasm based system of cytoplasmic male sterility in Brassica juncea: Reappraisal of fertility restoration and agronomic potential

Cytoplasmic male sterility (CMS) system based on the cytoplasm from Moricandia arvensis (mori) was investigated for fertility restoration and agronomic potential. Fertility restorer gene for mori CMS was introgressed from cytoplasm donor species as all the evaluated Brassica juncea genotypes (155) acted as sterility maintainers. The allosyndetic pairing between M^a and the A/B genome chromosomes in the monosomic addition plants (2n= 18II + 1M^a) facilitated the gene introgression. Partial fertility restoration (43–52% pollen grain stainability) in F₁ hybrids and absence of segregation for male sterility in F₂ progenies suggested gametophytic control of fertility restoration. The pollen fertility in the F₁ hybrids was, however, sufficient to ensure complete seed set upon bag selfing. Introgression from M. arvensis also helped in correction of chlorosis associated with mori cytoplasm in CMS and fertile alloplasmic B. juncea plants. Yield evaluation of thirty F₁ hybrids having the same nuclear genotype but varied male sterilizing cytoplasms (mori, oxy, lyr, refined ogu), in comparison to respective euplasmic hand bred control hybrids, allowed an estimate of yield penalty associated with different CMS systems. It ranged from 1.8% to 61.6%. Hybrids based on cytoplasmically refined ogu were most productive followed by those based on cytoplasmically refined mori CMS. The male sterility systems emanating from somatic hybridization were found superior than those developed from sexual hybridization.     

A simple method to control the seed purity of japonica hybrid rice varieties using PCR-based markers

Cytoplasmic male sterility (CMS) by the cms‐bo cytoplasm and its restoration by the nuclear restorer gene, Rf‐1, are used for seed production of japonica hybrid rice varieties. To produce pure hybrid seeds, a prerequisite is to properly manage the seed purity of parental lines, especially CMS lines. In this study, three dominant polymerase chain reaction (PCR)‐based markers (M1, M2 and M3) were developed to detect mutual contamination in seed batches of CMS lines, maintainer lines, restorer lines and hybrids. M1 detected the mitochondrial sequence that was present in the cytoplasm of common japonica varieties and absent in the cms‐bo cytoplasm. M2 and M3 detected the chromosomal sequence related to the Rf‐1 allele in restorer lines and the rf‐1 allele in common japonica varieties, respectively. By the strategic use of these markers, japonica hybrids and their parental lines could be efficiently distinguished from each other. Furthermore, sensitivity tests for the three markers with a series of crude DNA samples prepared from polished grains demonstrated that these markers could detect one contaminating grain among 500 or 1000 grains. Therefore, the bulk PCR analyses with the markers developed here probably make it possible to control the seed purity of japonica hybrids properly by selecting appropriate seed batches of their parental lines quickly and efficiently.     

Seed productivity test of CMS lines of Japanese bunching onion (Allium fistulosum L.) possessing the cytoplasm of a wild species, A. galanthum Kar. et Kir.

In a previous study, we developed male sterile lines of Japanese bunching onion (Allium fistulosum L.) possessing the cytoplasm of a wild species, A. galanthum Kar. et Kir., by backcrossing. To evaluate seed productivity of the male sterile lines in practise, they were crossed with the male fertile line, cultivar 'Kujyo', using honeybees as pollinators under field conditions. The number of florets and seeds per inflorescence, seed set and seed germination of the material were investigated. Although variation was observed among the male sterile lines, there were several lines having seed productivity equal to cultivar 'Kujyo'. Our data demonstrate that the male sterile lines of A. fistulosum possessing the cytoplasm of A. galanthum are useful as seed parents for the commercial F seed production of A. fistulosum.