近15年国家自然科学基金稻、麦类作物遗传育种领域项目申请情况分析

国家自然科学基金是国家支持基础研究的主要渠道之一。本文以15年(1998—2012年)来国家自然科学基金中稻、麦类作物遗传育种面上类项目申请数据为依据,对稻、麦类作物遗传育种学研究的现状与趋势从研究领域和研究层次2个维度进行了深入分析。分析数据显示,15年来稻、麦类各类型项目申请量呈上升趋势,其中稻类项目的申请总量高于麦类项目。从研究领域来看,稻类研究项目申请量最多的是发育生物学,占稻类申请量的37.4%;其次是抗性,占27.6%。麦类作物研究主要集中在抗性研究领域上,占麦类申请量的38.1%;其次是发育及品质,分别占23.7%和21.5%。从研究层次来看,随着水稻基因组测序的完成,稻类研究领先于小麦研究。稻类研究项目申请量最多的基因克隆与功能分析,占稻类申请量的41.6%;其次是分子标记与基因定位,占28.8%。麦类研究申请量最多的是分子标记与基因定位,占麦类申请量的36.5%;其次是基因克隆与功能分析,占28.2%。综合国内外研究现状,建议今后在继续加强对围绕高产、优质、高效、抗逆等研究持续资助的基础上,积极支持将基因组学、生物技术和生物信息学与传统作物学相结合的基础研究。     

Trial heterogeneity and variance models in the genetic evaluation of potato tuber yield

Genetic evaluation aims to identify genotypes with high empirical breeding values (EBVs) for selection as parents. In this study, 2157 potato genotypes were evaluated for tuber yield using 8 years of early‐stage trial data collected from a potato breeding programme. Using linear mixed models, spatial parameters to target greater control of localised spatial heterogeneity within trials were estimated and variance models to account for across‐trial genetic heterogeneity were tested. When spatial components improved model fit, correlations of errors were mostly small and negative for marketable tuber yield (MTY) and total tuber yield (TTY), suggesting the presence of interplot competition in some years. For the analysis of multi‐environment trials, a variance model with a simple correlation structure (with heterogeneous variances) was the most favourable variance structure fitted for TTY and PTY (per cent marketable yield). There was very little difference in model fit when comparing a factor analytic structure of order 2 (FA2) with either FA1 or simple correlation structures for MTY, indicating that simple variance models may be preferable for early‐stage genetic evaluation of potato yield.     

Identification of marker alleles linked to fire blight resistance QTLs in apple genotypes

Molecular marker analysis can be an effective tool when searching for new fire blight resistance donors. It can speed up the breeding process as well, even though many of the available markers linked to fire blight resistance QTLs have not yet been tested by screening a large number of cultivars. The aim of this study was to search for alternate sources of the three major QTLs of fire blight resistance; FBF7, FB_MR5 and FB_E, as well as to test the efficiency of some markers linked to minor QTLs. Altogether, nine primer pairs were used on 77 genotypes including new Hungarian cultivars and old apple cultivars from the Carpathian basin. Several marker alleles of FB resistance QTLs have been detected in the screened genotypes, most importantly the alleles coupling with FB_MR5 in the old cultivars ‘Kéresi muskotály’, ‘Szabadkai szercsika’ and ‘Batul’. We propose these cultivars as the first available resistance donors of FB_MR5 instead of the crabapple Malus × robusta 5. The results also bring new information regarding the resistance alleles of new Hungarian cultivars and selections.     

Implications of the number of years assessment on recommendation of common bean cultivars

In the common bean crop in Brazil, the requirement of the value for cultivation and use trials is that these experiments must be conducted over two years in three locations per region. Information in regard to the necessary number of years to ensure precision in cultivar recommendation and the influence of evaluated years in the estimation of the GE interaction are still scarce. Using grain yield of five check varieties assessed over 11 years in three sowing seasons per year, the aims of this study are as follows: to measure the relative contribution of the GE interaction, evaluating the implication of the number of years in the estimates of the GE interaction, and infer how many years are needed to ensure precision in cultivar recommendation. For instances, analysis of variance was carried out involving all environments and also combinations of years. The results showed that the GE interaction was greater than all other cross‐effects involving lines. The use of at least two years allows good coincidence in cultivar recommendation compared to the whole period. Increasing the evaluation time is a good strategy, especially when it is difficult to grow three different sowing seasons.     

Androgenic capability among genotypes of winter and spring barley

Variable efficiency of androgenesis remains a serious problem in many species of cereals. It is still unclear what makes certain genotypes more amenable to androgenesis than others. This study was undertaken to quantify the previously suspected advantage of winter barley genotypes over spring ones with regard to regeneration efficiency in anther culture. The material consisted of 40 barley hybrids originating from Polish breeding companies. The number of androgenic structures per 100 anthers did not differ significantly between analysed groups (119 vs. 152 non‐significant), but the average regeneration of green plants per 100 anthers was five times higher in winter genotypes (6.4 vs. 1.3). The incidence of albinism was lower for the winter than for the spring materials (70% vs. 90%), while the rate of spontaneous chromosome doubling was similar in both groups (58% vs. 56%). The results strongly support the notion that winter genotypes are more amenable to androgenesis and this may be a consequence of their better adaptation to stress conditions.     

棉花双隐性核雄性不育的利用研究

ｍｓ５ｍｓ５受两个隐性基因控制雄性不育，它来源于美国抗风暴品系，没有有害因子存在，用它为母本生产杂交种，具有较好的杂种优势。Ｆ２代群体中只有１／１６不育株，Ｆ２代种子可以利用。     

甜（辣）椒耐低温弱光品种筛选方法初探

通过在不同的低温弱光条件下，对８个代表性品种的冷害发生发展规律的研究，初步确定：１５℃／５℃（昼／夜）、光照强度４０００ｌｘ、光照时间８ｈ、处理１５天，是耐低温弱光品种的适宜选择压力。在此条件下，耐低温品种不出现伤害症状和落叶现象，叶片生长速度快；不耐低温品种生长缓慢，落叶严重，且生长点呈黑褐色，以至干枯。品种间差异显著。同时，耐低温品种叶片叶绿素含量增加，而不耐低温品种叶绿素含量下降。这一结果为进一步完善耐低温弱光品种的鉴定方法提供可靠的依据     

Incidence and molecular markers of 2n pollen in Populus tomentosa Carr.

Microscopic examination, amplified fragment length polymorphism (AFLP) and SCAR (sequence-characterized amplified region) molecular markers were employed to determine the incidence of 2n pollen (unreduced pollen) in Chinese white poplar (Populus tomentosa Carr.) and to identify related molecular markers. The presence of a parallel and tripolar spindle at metaphase II and the absence of cytokinesis at telophase II were found to be determining factors in 2n pollen formation. A group of 298 clones that originated from their indigenous areas were investigated for the production of 2n pollen based on pollen size differences, both within a clone and between n and 2n pollen. Pollen grains were collected from 224 of the clones, six of which were subsequently determined to produce only normal pollen; the remainder produced 2n pollen at different frequencies (0.6–21.9%). The frequency at which 2n pollen was produced was significantly and highly significantly different among and within indigenous populations, respectively. Clones produced by the six normal and twenty-two 2n pollen clones were selected for AFLP analysis. Following an initial screening with 55 primer combinations, the E50-M38 (CAT/ACT) primer was identified: it generated a PCR fragment (246 bp) from the normal clones, but not from the 2n pollen producers. In addition, the E31-M50 (AAA/CAT)-amplified DNA fragment (204 bp) was present in 2n pollen producers, and absent in normal clones. These two discriminating AFLP markers were developed into easily detectable SCAR (sequence characterized amplified region) markers which can be used in combination with previously developed AFLP markers to distinguish between normal and 2n pollen clones.     

The long and winding road leading to the successful introgression of downy mildew resistance into onion

Downy mildew resistance originating from Allium roylei Stearn provides a complete resistance to onions and is based on one, dominant gene. Since A. roylei can successfully be hybridized with onion (A. cepa L.), a breeding scheme aimed at the introgression of this gene was initiated ca. 20 years ago. Several setbacks in this programme were encountered, firstly the identified molecular marker linked to the downy mildew resistance locus became increasingly difficult to use and finally lost its discriminating power and secondly the final step, making homozygous introgression lines (ILs), turned out to be more difficult then was hoped. GISH analysis showed that the chromosomal region harbouring the resistance locus was the only remaining piece of A. roylei in the nuclear background of onion and it also confirmed that this region was located on the distal end of chromosome 3. It was hypothesized that some factor present in the remaining A. roylei region was lethal when homozygously present in an onion genetic background. The identification of an individual with a smaller and more distally located introgression fragment and homozygous ILs in its progeny validated this hypothesis. With the help of these nearly isogenic lines four AFLP^® markers closely linked to the resistance gene were identified, which can be used for marker-aided selection. The introduction of downy mildew resistance caused by Peronospora destructor into onion is a significant step forward in the development of environmentally-friendly onion cultivars.     

Factors affecting oat haploid production following oat × maize hybridization

Doubled haploids (DHs) are becoming increasingly important in crop breeding programmes but methods for producing oat DHs remain inefficient. In this study haploid and DH oat plants were produced using the oat × maize hybridization method. Factors influencing the rate of caryopsis and haploid embryo production including genotype, post‐pollination plant growth regulator application and temperature were investigated. The four growth regulators tested showed significant differences in their capacity to induce caryopsis formation with dicamba producing the highest numbers of caryopses, followed by picloram, 2,4‐dichlorophenoxyacetic acid (2,4‐D) and gibberellic acid (GA₃). No significant differences were observed between these growth regulators for their effect on embryo production. The concentration of dicamba was also important and was found to influence caryopsis but not embryo production, with 50 and 100 mg/l dicamba producing significantly more caryopses than 25 or 5 mg/l. Temperature had a significant impact on both caryopsis and embryo production with the magnitude and direction of response depending on genotype. Rates of haploid embryo production observed were between 0.8% and 6.7% of the pollinated florets. The proportion of haploids, which survived and were successfully doubled with colchicine following transfer to soil was between 72% and 81%.