基于熵权赋权法的灰色系统理论在燕麦品种综合评价中的应用

基于熵权赋权法、运用灰色系统理论中的灰色关联度法对10个燕麦品种从生产性能、品质以及抗倒伏性、抗病性等方面进行了综合评价。结果表明,综合表现较好的有青永久118、青永久474及青永久94;表现一般的有青永久478、青永久81和青引1号;表现最差的是青永久136、CNC、黄燕麦和青永久12。聚类分析也得到相同结果,说明基于熵权赋权法的灰色系统理论可以用于燕麦种质资源的综合评价。     

紫花苜蓿原生质体游离条件的研究

以选育的XN-1型紫花苜蓿种子发育5～7d的子叶、下胚轴及其诱导的愈伤组织和分化的无菌苗的叶片为材料,研究了不同的酶种类及组合、酶液浓度、酶解时间以及离心转速和时间等因子对其原生质体游离的影响.结果表明:子叶及第2次继代的愈伤组织为最好的游离材料;最佳酶液组合和酶解时间分别为纤维素酶2% 果胶酶0.5%和8h;最佳离心转速和离心时间分别为500r/min和6min.     

The Performance of Pea (Pisum sativum L.) and its Role in Determining Yield Advantages in Mixed Stands of Pea and Oat (Avena sativa L.)

On a brown warp soil (Fluventic Eutrochrept) near Goettingen, Germany, conventional leafed pea ( Pisum sativum L. cvs Messire and Bohatyr) and semileafless types (cvs Profi, Juno and Azur) were grown in mixed stands together with oat ( Avena sativa cvs Alf and Lutz) in substitutively designed experiments from 1995 to 1997. Oat was the dominant component. Crowding coefficients for oat averaged 7.4. No relationship could be detected between the crowding coefficient of oat and any yield advantage from the mixture. Crowding coefficients for pea varied substantially, between 0.1002 (Juno and Alf in 1996) and 0.2979 (Bohatyr and Alf in 1996). Crowding coefficients for semileafless pea cultivars were smaller than for conventional leafed types. The yield advantage of the mixture increased as the crowding coefficient of pea increased. The maximum yield increase for the mixture was achieved when the relative yield total (RYT)=1.17 or + 11 dt grain DM ha^–1 for mixtures of the long-strawed conventional leafed cultivars Bohatyr and Alf (in 1996). The crowding coefficients of pea were positively correlated with the level of symbiotically fixed N₂ in the mixed stands. When N₂ fixation with mixed cropping was about 30 kg N ha^–1, RYT was unity. Increasing symbiotic N₂ in the mixtures resulted in increasing yield advantages in the mixture. Short-strawed pea cultivars seem unsuitable for mixing with oat. Plant height of pea appeared to be more important than plant leaf type. Accordingly, mixtures containing the long-strawed semileafless pea cultivars Profi and Alf were more successful. It is concluded that increased competitiveness of the pea component in the mixture with oat entails increasing the level of symbiotic N₂ fixation including resource complementarity and thus yield advantage in the mixed stands.     

4PU-30对水稻叶片衰老与活性氧代谢的影响

以水稻汕优63离体和连体叶片为材料,研究了4PU-30对水稻叶片衰老和活性氧代谢的影响。4PU-30对水稻离体叶片和抽穗后连体叶片的衰老有明显的延缓效应。叶片中活性氧清除酶活性和脂质过氧化的变化表明,4PU-30能延缓叶片衰老过程中SOD和CAT活性的下降,减缓O·₂产生的速率和MDA的积累,这是其延缓水稻叶片衰老的主要生理原因之一。     

Effects of the two most common Wx alleles on different genetic backgrounds in rice

Wx^a and Wx^b are the most common alleles of the Wx gene in Asian cultivated rice. The difference between them is responsible for differences in the levels of the Wx gene product in the endosperm, as well as in amylose content, which is an important determinant of the quality of edible rice. Since Indica rice mostly carries the Wx^a allele, we introduced the Wx^b allele into Indica‐type rice (IR36) from a Japonica‐type rice (T65) by repeated backcrossing. In the near‐isogenic line (IR36 Wx^b), the level of the Wx gene product was reduced and, as expected, the level of amylose. However, IR36Wx^b had a lower amylose content than the recurrent parent of T65 with the Wx^b allele. The results suggest that the Indica (IR36) background might lower the amylose content more than the Japonica (T65) background when the Wx allele is the same. The possible importance of modifiers that regulate expression of the Wx gene is also discussed in relation to improvements in the grain quality of rice.     

云南籼稻每公顷15吨高产的产量及其结构分析

本文利用ＩＲ７２汕优６３等材料,在云南永胜县涛源乡高产环境下,对高产品种的产量及其构成因素分析研究表明,高产品种的结实率与产量呈极显著的正相关,相关系数为０．８１８１;有效穗与穗粒数呈显著负相关,有效穗、穗粒数、结实率和千粒重对产量的直接效应均为正值,其中以结实率的影响力最大,直接通径系数为０．７９７９。穗数、大穗型和中间型的品种（组合）均能获得１５t/hm^2的产量,但穗粒协调的中间型品种更易获得１５t/hm^2的高产。云南涛源获得每公顷１５t以上产量就在于高水平的穗数群体下,仍能协调与穗粒数及产量的关系。使得粒数和粒重达到相当的水平,１９９６年汕优６３获得１５t/hm^2产量的产量结构为,每平方米穗数489,每穗实粒数101．4千粒克30．7g;桂朝2获15．18t/hm^2的产量结构为每平方米穗数433,每穗实粒数126．2,千粒重27．3g。     

用农杆菌将Bt基因导入水稻愈伤组织的研究

从水稻成熟胚诱导出的愈伤组织经继代培养后可以产生大量的胚性愈伤组织。通过采用农杆菌共培养法转化上述胚性愈伤组织,在附加羧苄青霉素Ｃｂ（５００ｕｇ／ｍＬ）和卡那霉素Ｋｍ（５０ｕｇ／ｍＬ）的选择培养基上进行抗性愈伤组织的筛选,在附加羧苄青霉素Ｃｂ（５０ｕｇ／ｍＬ）和卡那霉素Ｋｍ（２５ｕｇ／ｍＬ）的分化培养基上诱导抗性芽。ＧＵＳ酶活性检测和ＰＣＲ检测结果均为阳性,证明外源目的基因（Ｂｔ）已在寒地水稻抗性愈伤组织中整合并表达。抗性再生植株的ＧＵＳ酶活性及ＰＣＲ检测正在进行中。     

盐渍条件下苜蓿和羊草生长与营养吸收的比较研究

通过室内模拟试验,研究了盐分对苜蓿和羊草生长与营养吸收的影响,结果表明,盐度处理对羊草植株生长的影响低于对苜蓿的影响,羊草较苜蓿更为耐盐。苜蓿的蒸散量和净光合速率（NPn),尤其是日最大净光合速率受盐分的影响比羊草显著。随土壤含盐量的增加,苜蓿和羊草植株N、P含量无明显变化,K含量迅速降低,而Na含量急剧增加。苜蓿与羊草相比,苜蓿则有相对较低的K特定吸收率（SAR）和高的Na特定吸收率（SAR）。     

A Comparative Study of SSR Diversity in Chinese Major Rice Varieties Planted in 1950s and in the Recent Ten Years （1995-2004）

Forty pairs of SSR markers were used to compare the genetic diversity changes in 151 Chinese major rice varieties planted in 1950s and in the recent ten years. Of 40 SSR loci, 39 were found to be polymorphic while one locus (RM479) monomorphic. A total of 213 alleles were identified from the 39 polymorphic loci. The average number of alleles per locus (Na) was of 5.5, ranging from 2 to 11. Nei’s gene diversity index (He) varied drastically among loci from 0.309 at RM174 to 0.869 at RM418, with an average value of 0.649. There existed significant difference in SSR allelic diversity between indica and japonica subspecies, and indica had more variation than japonica both in Na and He. By comparison with the genetic changes in Na and He, it was revealed that the varieties planted in 1950s had more alleles and higher He than those in the recent ten years both for indica and japonica rices. The difference between two subspecies for Na was significant in a tendency over time (indica: z = 2.677, P = 0.007; japonica: z = 3.441, P = 0.001), but not significant for He (indica: z = 1.471, P = 0.141; japonica: z = 1.932, P = 0.053). Analysis of molecular variance (AMOVA) indicated that there existed significant difference (P < 0.05) in genetic variation between the two periods, of which more genetic variation was contributed by indica (Fst = 0.050) and japonica (Fst = 0.082) subsets. Using locus-by-locus AMOVA procedure, significant genetic differentiations were observed in 13 loci (RM21, RM128, RM147, RM169, RM190, RM221, RM231, RM251, RM253, RM317, RM341, RM418, and RM478) for indica varieties and 11 loci (RM101, RM135, RM152, RM159, RM169, RM190, RM251, RM253, RM311, RM418, and RM478) for japonica ones between the two periods. It was found some alleles had been lost in current major rice varieties as comparing with those in 1950s. Therefore, it should be necessary to exploit more alien elite genetic resources for extension of genetic background in current rice breeding program.     

马来西亚普通野生稻增产QTL的分子标记辅助选择及其育种效果

位于马来西亚普通野生稻（Oryza rufipogon）第1和第2染色体上的两个主效增产QTL（yld1.1和yld2.1）分别具有18%和17%的增产效果。为探明野生稻增产QTL对杂交水稻产量性状改良的效果,以超级杂交稻亲本9311为受体和轮回亲本,马来西亚普通野生稻为增产QTL供体进行杂交和连续回交,并利用与这两个增产QTL紧密连锁的4个SSR分子标记对回交群体进行分子鉴定和辅助选择。产量比较试验结果显示, 育成的携带野生稻增产QTL的9311改良系比受体9311增产,主要表现为有效穗数和每穗总粒数显著增加;携带野生稻增产QTL的稳定株系所配杂交组合也比对照显著增产。研究表明野生稻增产QTL yld1.1和QTL yld2.1导入栽培水稻品种的遗传背景后能显著提高产量潜力,可作为超级杂交稻育种重要资源。