新型细胞标记技术在酿酒酵母原生质体融合育种中的应用研究

本研究用酿酒酵母原生质体融合技术使两株酵母发生融合,通过用营养要求测定,交配型测定、细胞体积测定、DNA含量测定,筛选出13株融合株,再经免疫测定,得到同样的鉴定结果.表明免疫测定技术在酿酒酵母原生质体融合育种中作为亲本细胞标记是可行的,具有较高实用价值.     

巴林脐橙叶片元素含量适宜指标研究

生物统计表明：采样地点及年份间的差异对巴林脐橙叶片元素含量有明显的影响;叶片微量元素含量的变异系数均显著高于大量元素。初步提出丰产巴林脐橙叶片元素含量的适宜指标：N2．8～3．3,P0．14～0．18,K1．4～2.1,Ca2.0～4.0,Mg0.25～0.45（以上单位×10-2）,Cu5～18,Zn20～50,Mn20～100,Fe50～160,B25～100（以上单位×10－6）上列指标可供营养诊断之参考。     

A comparative analysis on the distribution of nymphal populations of some leaf- and planthoppers on rice plant

The frequency distribution of the number of nymphs per hill of rice plant were analyzed for three species of rice leaf- and planthoppers, Nilaparvata lugens, Delphacodes striatella and Nephotettix cincticeps, based on the sampling data obtained during their last generations in the paddy field. For every species concerned, individual distributions were proved to be contagious and to fit well to the negative binomial distribution. Further, it was found that the value of negative binomial parameter k is so stable for same species that a single value of k is applicable for a series of counts with different means, whereas that k differs remarkably among different species: if the reciprocal of the weighted estimate of common k which is an adequate index measuring degree of contagiousness of the distribution, is compared among different species, it is higher in the order of Nilaparvata, Delphacodes and Nephotettix. The ecological and practical implication of constancy and heterogeneity within and among species was discussed respectively as to the value of parameter k.     

慈竹母株大小对克隆生长的影响

 克隆生长在慈竹种群更新中占有重要地位。本文以基径和生物量两个指标同时衡量慈竹(Neosinocalamus affinis)的母株大小,并分析了母株大小对新竹笋产生、竹笋大小和根茎大小的影响。结果表明：1）慈竹的成竹基径与一级母株基径、二级母株基径以及与2龄和3龄母株平均单株生物量呈正相关,但是成竹基径随一级母株基径增加比随二级母株基径增加而增加的速率快得多;2）慈竹母株大小与各样方中出笋数、活笋数和死笋数无显著的正相关;3）发笋母株的基径显著大于未发笋母株,但发一个笋母株与发两个以上笋母株的基径无显著差异;4）母株基径、2龄和3龄母株平均单株生物量都与根茎的长度和粗度呈显著正相关,且竹笋基径与根茎粗度也呈显著的正相关。母株大小对慈竹竹笋的影响是通过影响根茎实现的。总之,慈竹的克隆生长在个体水平受母株大小制约。     

中华绒螯蟹亲蟹的饥饿代谢研究

1998年 10～ 12月 ,对体重为 5 4 .5 9(± 2 .37) g的亲蟹在 2 0 (± 0 .5 )℃温度条件下进行饥饿实验 ,研究了饥饿对中华绒螯蟹亲蟹代谢的影响 .结果表明 ,经过 30d的饥饿处理 ,亲蟹的耗氧率降低为摄食状态的 5 0 .0 % ;CO2 排出率减小为摄食状态的 6 3.4 % ;NH3 N排泄率减小为 5 9.1% .耗氧率和CO2 排出率、NH3 N排泄率的变化差别较大 ,耗氧率的减小可分为 4个阶段 ,而CO2 排出率和NH3 N排泄率的减小仅可分 3个阶段 .与此同时 ,亲蟹的标准代谢水平同样受到饥饿的影响 ,饥饿 30d后 ,由 4 .4 5J·g-1·h-1减小为 2 .36J·g-1·h-1;在饥饿亲蟹的代谢中 ,脂肪消耗最多 ,其次是碳水化合物 .     

An alternative statistic for identifying lines useful for improving parents of an elite single cross

Summary Theory and methods for identifying inbred lines (I _w) with favorable dominant alleles not present in an elite single cross (I ₁×I ₂) have been developed recently. Selected I _w lines can be crossed to I ₁ or to I ₂ to transfer new favorable alleles to the single cross. However, favorable alleles already present in the single cross may be lost during selection. It is important to consider both potential gain of favorable alleles from I _w and loss of favorable alleles already present in I ₁×I ₂. The net improvement statistic (NI)=maximum [(I ₁×I _w-I ₁xI ₂)/2, (I ₂×I _w-I ₁×I ₂)/2] estimates the number of loci where favorable alleles can be gained minus the number of loci where favorable alleles can be lost in the single cross. Because I ₁×I ₂ is constant in an experiment, the method reduces to choosing I _w lines with the best mean performance in combination with either I ₁ or I ₁. NI was compared to estimators previously proposed for identifying lines, namely: (1) minimally biased estimates (G) of favorable dominant alleles present in I _w but not in I ₁ and I ₂; (2) minimum estimate of an upper bound (UBND) on G; and (3) predicted three-way cross (PTC) performance. Based on a set of maize (Zea mays L.) grain yield data, correlations among the four estimators were relatively high, but indicated that rankings of I _w lines vary with the particular estimator used. Rankings of three I _w lines based on the frequency of F₂ test crosses superior to B73×Mo17 were identical to rankings based on NI, but differed from rankings based on G, PTC, and UBND. NI also was the best predictor of the mean of the upper 10% ({ovx}_0.1) of (I ₂×I _w) F₂×I ₁ or (I ₁×I _w) F₂×I ₂ test crosses based on simulated data. Being a simple statistic highly correlated to {ovx}_0.1, NI may be useful in applied breeding programs.A contribution from Lifaco Genetics, a Groupe Limagrain company     

高粱穗部主要性状的配合力分析

以4个高粱不育系13163A、1358A、128A和407A,以及6个恢复系9.1R、213R、272R、381R、矮182R和早21R为试验材料,按照不完全双列杂交设计(NCII),对其F1的穗部主要性状进行配合力分析。结果表明:亲本穗部主要性状存在显著的遗传差异,主要表现为加性基因效应遗传的性状有:穗长、一级枝梗数、二级枝梗数、穗粒数;狭义遗传力大小顺序分别为:二级枝梗数一级枝梗数穗长穗粒数穗粒重千粒重。不同亲本的一般配合力(GCA)和特殊配合力(SCA)在不同穗部性状间存在较大差异。不育系407A和恢复系早21R、9.1R是综合性状较好的亲本材料,利用它们可组配出产量较高的杂交组合。恢复系272R组配的杂交种具有穗粒数较多、千粒重较小的特点,能满足市场上对小粒高粱的需求。深入分析高粱杂交亲本穗部主要性状表现,有利于对亲本材料的进一步了解和利用。     

Parent/offspring Relations for a Fitness Related Character

Some parent/offspring relations of a quantitative character are discussed, in particular in relation to the mean change from one generation to the next. It is shown that the prediction of this “progress” as the heritability multiplied by the selection differential takes only the slope of the parent/offspring relation into account and holds if, and only if, the population mean is a fixpoint of the mid-parent/offspring regression in the case of a character that is unrelated to sex. In particular, two examples show that this may not be the case if the character is related to fitness by pleiotropic effects of single genes.     

Relationships between body size,reproductive traits,and food resource in three species of tropical flesh flies

Intra- and inter-specific comparisons in progeny size and clutch size were used to identify possible selection pressures acting on three sympatric species of ovoviviporous flesh flies. Both progeny and clutch sizes increased with body weight of the female parent in all species. There was no evidence for a simple trade-off between the two traits. In one species, the larger the female adult the smaller the relative biomass of larvae per clutch (total weight of larvae/body weight of female parent). Female flies produced similar progeny and clutch sizes over successive batches. Variation in progeny size did not influence either larval survival or duration of larval and pupal development. However, larger first instar larvae tended to form larger pupae in two of the species. The experiments testing the effect of progeny size on pupal weight under limited food conditions suggest a selective advantage for larger progeny size.