以柑橘多胚性二倍体母本倍性杂交培育三倍体

2009-2012年,以柑橘8个多胚性二倍体品种为母本与近年始花的5个异源四倍体体细胞杂种和1个同源四倍体分别杂交,培育三倍体新种质。连续4年共配置15个杂交组合,授粉4 442朵花,坐果1 484个,平均坐果率33.4%;用于幼胚挽救的果实1 075个,共培养幼嫩种子12 578颗,经生芽、生根诱导获得再生植株2 832个;以流式细胞仪对所有再生植株倍性检测,15个组合共获得三倍体401个,四倍体121个;移栽成活三倍体349个,四倍体98个。对W. 默科特 × NH组合89个株系的三倍体的SSR分子鉴定表明,所有三倍体后代均为双亲的有性杂种。     

基质效应对不同蔬菜中有机磷农药残留检测的影响

采用NY/T 761-2008方法,通过使用不同基质,对5类蔬菜中10种有机磷农药残留进行了检测,明确了不同的基质溶液对检测结果的影响程度。建议今后的检测过程中合理地利用基质效应,尽量采用蔬菜分类检测,不同种类的蔬菜采用不同的基质,这样能够大大减少基质带来的干扰,提高结果的准确性。     

Ploidy manipulation and introgression breeding in Darwin hybrid tulips

Meiotic polyploidisation via crossing with 2n gamete producing genotypes and interploidy crosses are two of the main methods currently used to obtain polyploid tulips. In our study diploid 2n gamete producing F₁ hybrids of Darwin hybrids (Tulipa gesneriana × Tulipa fosteriana) and triploid hybrid resulting from ‘Rhodos’ × ‘Princeps’ cross were used as pollen donor and crossed with cultivars of T. gesneriana in the following combination: 2x × 2x, 3x × 2x, 2x × 3x, and 3x × 3x. The progenies resulting from crosses at diploid level were mostly diploid, whereas a few seedlings were triploid. In 3x × 2x crosses aneuploids with chromosome constitution in between triploid and tetraploid (43–45 chromosomes) were predominant, but also one tetraploid (2n = 4x = 48) and four pentaploids (2n = 5x = 60) were obtained. In 2x × 3x crosses most progenies were triploid with the exception of a few aneuploids (3x + 1 and 3x ? 1), whereas in 3x × 3x cross diploid and aneuploid genotypes were recorded with chromosome number varied from 27 to 34. These results indicate that triploid parents produced aneuploid as well as euploid (x, 2x, 3x) gametes and that success in ploidy manipulation in tulip depends to a large degree on the ploidy level of the parental genotypes used for hybridization. Genome constitution of selected population of F1 and BC1 hybrids was analyzed through genomic in situ hybridization (GISH). GISH analysis of the BC1 showed a considerable amount of intergenomic recombination which is desirable for introgression breeding.     

Evaluation of genotypic variation in heat tolerance of tall fescue by functional traits

Tall fescue is an important cool season turfgrass. Summer high temperature negatively affects the performance of tall fescue in transitional and warm climate zones. To identify heat tolerant material, 120 tall fescue accessions from different regions of the world were collected and subjected to high temperature under the greenhouse and the growth chamber conditions. Average temperature was 43 °C in the greenhouse trial. Meanwhile, in the growth chamber trial there were 38/30 °C (day/night) and 25/16 °C for heat stress and control, respectively. Leaf water content, leaf dry weight, leaf fresh weight, growth rate (GR), turf quality (TQ), survival rate (SR), chlorophyll content (Chl), evapotranspiration rate (ET) and electrolyte leakage were determined. Significant effects of accessions, duration time and heat treatment on most characteristics were observed. Wild accessions exhibited higher variations in most of the studied traits than commercial cultivars. There were differences in GR and ET with greater variation coefficients than other traits between accessions, suggesting GR and ET could be effective indices for evaluating heat tolerance of tall fescue accessions. Three principal components in growth chamber trial and two principal components in greenhouse trial were extracted. Principal component analysis indicated that common PC1, correlated with TQ, SR and Chl, was named as “turf performance component”, which explained 43.17 % and 39.24 % of genetic variations in the greenhouse trial and the growth chamber trial, respectively. PC2 that defined as “growth potential component” could explain 23.26 % of total variability in the greenhouse trial and 20.36 % in the growth chamber trial. PC3 was named as “leaf water potential component”. Two regression models (F = 0.65 × F1 + 0.35 × F2) and (F = 0.54 × F1 + 0.28 × F2 + 0.18 × F3) were formulated by factor analysis to evaluate heat tolerance of tall fescue accessions in greenhouse and growth chamber trials, respectively. Accessions from subtropical monsoon climate zone generally exhibited better heat tolerance. In contrast, accessions from East Asia showed more heat sensitive. Finally, five accessions including PI 598574, PI 608787, PI 559374, Pure Gold and PI 527504 were selected as heat tolerant accessions for future tall fescue breeding.     

Development and identification of a introgression line with strong drought resistance at seedling stage derived from Oryza sativa L. mating with Oryza rufipogon Griff

Drought stress is severely damaging during seedling stage of rice (Oryza sativa L.), which can lead to significant yield reductions. Dongxiang common wild rice (Oryza rufipogon Griff., hereafter referred to as DXWR), with strong drought resistance, could be a favorable genetic resource to improve the drought resistance of cultivated rice. Xieqingzao B (O. sativa L. ssp. indica, hereafter referred to as XB) is a representative maintainer line in hybrid rice breeding system in China. By using DXWR as donor parent, XB as recurrent parent, through continuous selfing, backcrossing and strict drought-resistant screening, we developed a strong and stable drought-resistant introgression line IL395 (BC₅F₁₀), whose ability of drought resistance was significantly increased than that of the recurrent parent XB at the seedling stage. Meanwhile, no significant differences existed among other major agronomic traits under normal condition, except for plant height. Physiological assessment revealed that IL395 exhibited a significant increase in levels of free proline and soluble sugars, which was associated with drought resistance. Whole genome marker analyses identified genomic segments of DXWR linking with RM171 and RM590 (chr. 10) and RM235 (chr. 12) that require further analysis as possible sources of drought resistance trait. These results suggest that DXWR could be a favorable genetic resource to improve the drought resistance of cultivated rice, and the IL395 might be a useful resource for excavating the drought-resistant genes from DXWR.     

基于博弈论法确定灌区运行状况综合评价指标的权重

为了确定综合评价过程中的指标权重系数是否合理,考虑评价结果的合理性和科学性.通过运用博弈论思想将主观的层次分析法(analytic hierarchy process,AHP)和客观的变异系数法(variation coefficient method, CVM)确定的权重系数集成得到最终的权重结果,并以“驱动力-状态-响应”(DSR)模型为基础,建立了一套大型灌区运行状况综合评价指标体系,将得到的主观权重、客观权重和综合权重分别运用到灌区运行状况的综合评价中进行实证分析,研究结果表明:基于博弈论确定的综合权重对灌区进行评价的结果既能体现决策者的主观要求,又能符合灌区实际运行状况.该方法过程简洁,结果科学、客观,具有较好的通用性.     

油茶果脱壳清选机组设计

为满足用户的需求,设计了油茶果脱壳清选机组,该机组能完成送料、分级、除杂和输送等流水作业,具有很大的推广价值和应用前景。      

不同栽培模式对恩施山地特色烤烟生长和干物质积累的影响

恩施山地是中国中间香型特色优质烟叶生产的适宜地区之一。探讨中间香型烟叶不同栽培因子的最佳组合模式对恩施山地烟农增产增收具有十分重要的意义。为此,比较分析了5种栽培模式下烟叶生长发育和干物质积累的动态变化规律。结果表明,5种栽培模式的根、茎秆和烟叶的干物质积累呈现“慢-快-慢”的模式。根、茎和叶器官干物质积累速率高峰期在移栽后60~75天左右, 干物质积累均符合二次多项式回归方程。干物质积累速率的大小为：叶片>茎>根。通径分析表明,最大叶面积对烟叶干物质积累的直接正作用最大,直接通径系数为2.152,茎杆干重对烟叶干物质积累起最大的负作用,其直接通径系数为-1.248。烤烟上等烟叶率与淀粉、还原糖与烟碱的直接通径系数分别为1.22、-0.369和0.145。还原糖通过淀粉和烟碱对烤烟上等烟叶率起的正作用为0.692。因此,通过改进栽培措施,增加茎秆和叶生长,降低根冠比,可以促进叶片干物质的积累。通过增加还原糖的含量,降低淀粉和烟碱的含量,可以提高烟叶的上中等烟率。烤烟经济性状和化学成分聚类分析表明,N4是适宜湖北恩施山地中间香型特色优质烟叶生产的最佳栽培模式,它在当地烤烟生长中具有广泛的应用前景。     

梅江盆地叶塘组紫色岩上发育土壤的物理性质研究

采用野外调查、取样和室内实验分析相结合的方法,研究了梅江盆地白垩系上统叶塘组（Kyt^2）紫色岩上土壤物理性质特征扣差异,结果表明：叶塘组紫色岩母质发育的土壤粘粒含量低而砂粒含量高,具有容重较大,比重相对偏小,孔隙度不高,自然含水量偏低的特点。从丘顶、丘腰到丘脚,土层逐渐增厚,土壤粘粒含量逐渐增加,砂粒含量逐渐减少,容重递增而比重减小。孔隙度表现出丘顶〉丘腰〉丘脚的趋势,含水量则表现出丘顶〈丘腰〈丘脚的趋势。针对情况,提出相应建议以维护紫色土利用的可持续发展。