基于主要表型性状的不同采集地斑茅种质资源遗传多样性分析

为提高斑茅种质资源利用效率,本研究对来自不同地区的76份斑茅种质资源的株高、茎径、节间长、叶长、叶宽、锤度6个表型性状进行遗传多样性分析。结果表明,来自不同地区的斑茅,6个表型性状平均变异系数在14.6%~53.4%之间,其中株高和节间长的变异系数相对较高,分别为53.4%和37.7%;锤度和叶长的变异系数相对较低,分别为19.1%和14.6%。株高、茎径、叶宽、叶长、节间长之间表现为极显著正相关,其中株高与节间长的相关系数最大,为0.818;锤度与株高、节间长呈负相关,相关系数分别为-0.232和-0.263。主成分分析表明,前2个主成分方差累计贡献率高达72.58%,其中第1主成分方差贡献率达到51.21%,第2主成分贡献率为21.37%。采用聚类分析方法,不同的种质资源被分为8大类群,第Ⅴ和Ⅵ类群的种质综合性状表现最好,这2个类群是优良的斑茅种质资源,可在甘蔗育种中加以挖掘利用。     

甜瓜嫩果皮颜色遗传规律研究

为探究甜瓜嫩果皮颜色的遗传规律,以甜瓜嫩果皮颜色为深绿色的S26和青色的S28为亲本材料,通过构建BC1群体,利用卡方测验,分析回交群体BC1的深绿色嫩果皮和青色嫩果皮的分离比例,开展甜瓜嫩果皮的遗传规律分析,以对嫩果皮颜色基因进行初步定位。结果表明：BC1群体表型表现为深绿色和青色2种,且群体比例为1∶1,从而确定颜色性状为单基因控制且深绿色为显性性状。通过分离群体分组分析法（BSA）和混池测序结果可以看出,控制甜瓜嫩果皮颜色的基因位于chr04的端部位置,这为后续基因的精细定位以及克隆提供了研究基础。     

Strategy to identify resistance to white mould associated with high yield for irrigated common bean in Brazil

Development of common bean cultivars with partial white mould resistance through breeding techniques has been a challenge in Brazil. As yet, lines/cultivars from breeding programmes have not been investigated for resistance; therefore, this study screened 107 lines/cultivars for their reactions to white mould in 14 preliminary trials conducted under irrigation. Thirteen resistant lines/cultivars (three of Andean origin) and six Mesoamerican cultivars (three intermediately resistant and three susceptible) were selected for further investigation. These lines/cultivars and the resistant control A195 were evaluated in six advanced trials and two straw tests to assess the effectiveness of the screening procedure. In 11 preliminary trials, screenings were performed under moderate/high or higher disease pressure. These pressures occurred in two advanced trials in which, when yields were averaged across moderate/high and high pressures, 10 Mesoamerican lines/cultivars selected for resistance yielded 14%, 23%, and 38% more than intermediately resistant cultivars, A195, and susceptible cultivars, with median disease ratings (1–9 scale) of 4.5, 5.7, 5.7, and 6.7, respectively. In the straw test, three Andean lines/cultivars (A195 included) and two susceptible cultivars in the field were among those with the highest levels of physiological resistance. Thus, field rating under high disease pressure and greenhouse rating did not correlate significantly, suggesting that field trials are critical to evaluating resistance and to identifying high-yielding beans. Therefore, lines/cultivars from breeding programmes assessed in field trials may provide a low cost and fast way to identify high-yielding bean cultivars with partial resistance to white mould in the subtropical southern hemisphere.     

Genetic variation of seedling traits responded to brassinosteroid and gibberellin inhibitors in maize (Zea mays) doubled haploid lines

The purpose of this study was to examine the genotypic variation in maize doubled haploid (DH) lines response to brassinosteroid and gibberellin inhibitors. Plant responses to hormone inhibitors were determined in growth chamber experiments using germination paper for three different seedling treatments: application of propiconazole (Pcz), uniconazole (Ucz) or water (control). Mesocotyl length (ML) was more sensitive to hormone inhibitors, especially to the Ucz treatment, than other seedling traits. ML was significantly correlated with other traits in the Ucz treatment. All the seedling traits showed moderate-to-high broad sense heritability values, ranging from 0.39 to 0.82. The Euclidian genetic distances of inbred line pairs ranged from 1.27 to 19.94, indicating there was a high level of variability across the maize DH lines used in this study. DH lines with extreme MLs were identified, which can provide valuable breeding resources for improving abiotic stress tolerance, and for further genetic studies.     

杉木全同胞家系的遗传分析及重要树冠因子的筛选

通过对5年生杉木6×6全双列杂交(Griffing Ⅲ)试验林的调查与分析,研究杉木若干性状的遗传与变异规律,并筛选决定理想株型的重要树冠结构因子,为杂交育种和杉木理想株型无性系选育提供科学依据。运用转化分析法来处理不平衡试验数据,结合配合力分析法、相关分析法和通径分析法,研究杉木遗传变异、基因作用方式和重要树冠因子的选择。通过对杉木若干性状进行研究,获得了不同性状遗传变异大小。结果表明,杉木材积、枝下高和饱满度等性状具有中度遗传变性,树高、胸径具有窄的遗传变异性,同时杉木改良性状具有中度以上的遗传力,因此杉木生长形质性状宜采用连续多世代改良;在杉木生长、形质性状和树冠结构性状中,12个研究性状有8个重要性状的基因作用方式以非加性遗传基因效应为主,杉木高世代育种亲本是多世代与高强度选择的产物,杂合体居多,杉木的多性状、高世代遗传改良以杂交育种为主;生长、形质和树冠结构性状间具有明显的遗传相关性,通径分析揭示:决定杉木理想株型育种中重要树冠结构性状是冠形率和树冠表面积大小。由此可见:杉木多性状、多世代连续改良以杂交育种为主,杉木无性系理想株型选择时,应注重冠形率和树冠表面积的作用。     

番茄萼片形态性状遗传分析

【目的】探索番茄萼片形态性状的遗传规律,为番茄新品种选育过程中萼片形态性状选择提供依据。【方法】以萼片包被(TI1101-1,P_1)和萼片上卷番茄(J53,P_2)材料为亲本,构建4个世代P_1、P_2、F_1和F_2遗传群体,用游标卡尺对4个世代番茄萼片形态及其形态性状(萼片长度、宽度、厚度、面积、上翘度、卷曲度)进行测量和统计,从而对番茄萼片形态性状的遗传规律、中亲优势、遗传模型进行分析。【结果】番茄F_1代正反交萼片形态一致,均为基平,说明萼片形态的遗传属于细胞核遗传。在F_2代分离群体中,萼片形态包被、基平、上翘、上卷的分离比为1∶34.4∶9∶1.6,即不符合孟德尔遗传规律,属于数量性状。萼片长度、宽度、厚度、面积、上翘度、卷曲度的中亲优势率分别为3.55%,-6.77%,-9.90%,0.51%,-32.42%,-62.02%。同时,运用植物数量性状主基因+多基因遗传分析法对6个萼片形态性状测量值的分析得出:萼片长符合2对等加性主基因+加性-显性多基因遗传模型(MX2-EAED-AD),萼片厚度、面积、卷曲度符合2对加性-主基因+加性-显性多基因遗传模型(MX2-ADI-AD),萼片宽度、上翘度符合2对加性-显性-上位性主基因+加性-显性-上位性多基因遗传模型(MX2-ADI-ADI)。萼片长度、宽度、厚度、面积、上翘度、卷曲度的主基因遗传率为42.59%～77.15%,多基因遗传率为0%～39.89%。【结论】该组合6个番茄萼片形态性状均受2对主基因控制,且主基因遗传率大于多基因遗传率,以主基因遗传为主。     

ISSR分子标记及其在树木遗传育种研究中的应用

在比较ISSR和其它分子标记的原理和特点的基础上,综述了ISSR分子标记在树木遗传多样性研究、亲缘关系及系谱分析、优良种质和品种鉴定及遗传连锁图谱的构建等领域的研究进展,指出了目前ISSR分子标记在树木遗传改良和辅助育种等研究领域存在的问题,并提出今后的研究方向。     

茄子果长遗传效应的初步研究

用长果自交系I521593和短果自交系SJ16212865为材料,通过自交、杂交和回交,获得亲本、F1、F2、BC1和BC2各世代,按照数量遗传学理论对6个世代群体的果长的遗传效应进行了研究。结果表明:茄子果长遗传方式属于数量遗传;其遗传效应符合加性—显性遗传模型,且以加性效应为主,在遗传中表现部分显性,有倾大值亲本的现象;控制果长性状的最少基因数目为3对;果长的狭义遗传力为71.01%。     

Generation of a uniform thymic malignant lymphoma model with C57BL/6J p53 gene deficient mice

Lymphoma is the third most common cancer diagnosed in children, and T-cell lymphoma has the worst prognosis based on clinical observations. To date, a lymphoma model with uniform penetrance has not yet been developed. In this study, we generated a p53 deficient mouse model by targeting embryonic stem cells derived from a C57BL/6J mouse strain. Homozygous p53 deficient mice exhibited a higher rate of spontaneous tumorigenesis, with a high spontaneous occurrence rate (93.3%) of malignant lymphoma. Because tumor models with high phenotypic consistency are currently needed, we generated a lymphoma model by a single intraperitoneal injection of 37.5 or 75 mg/kg N-methyl-N-nitrosourea to p53 deficient mice. Lymphoma and retinal degeneration occurred in 100% of p53^+/− mice administered with higher concentrations of N-methyl-N-nitrosourea, a much greater response than those of previously reported models. The main anatomic sites of lymphoma were the thymus, spleen, bone marrow, and lymph nodes. Both induced and spontaneous lymphomas in the thymus and spleen stained positive for CD3 antigen, and flow cytometry detected positive CD4 and/or CD8 cells. Based on our observations and previous data, we hypothesize that mice with a B6 background are prone to lymphomagenesis.