小麦-长穗偃麦草矮秆种质系的鉴定及遗传分析

矮源是进行小麦矮化育种的基础。本研究对2个小偃麦矮秆种质系31505-1和31505-2进行了分子鉴定和遗传分析。结果表明,31505-1和31505-2是2个不同的矮秆小偃麦易位系,31505-1中易位的偃麦草染色体片段位于2D染色体;对矮秆小偃麦种质系与不同株高材料杂交后代的株高和节间长度进行了分析,发现2个种质系的后代致矮率可达16%~23%,其株高的降低主要由节间长度的变化引起的,其中倒2节间与株高的变化相关性最高。本研究对拓宽小麦矮秆种质资源基础具有一定意义。     

Genetic characterization of Lens ervoides from Ethiopia

Summary A single population of the Mediterranean species Lens ervoides was located in Ethiopia and seeds were collected. Based on chromosomal arrangement and isozyme profile the Ethiopian L. ervoides is similar to populations of this species in the Mediterranean region. All hybrids between L. ervoides from Ethiopia and an accession of this species from Israel were dwarf, whereas hybrids between the former and an accession from Algeria were normal. Segregation in F₂ and BC generations indicated that the dwarf habit in lentil is governed by dominant alleles of two complementary genes designated df ₁ and df ₂. The dominant allele of another gene, dfi, inhibits the dwarf phenotype. The evolution of L. ervoides from Ethiopia and its potential as a genetic resource are briefly discussed.     

Effects of dwarfing genes on yield and yield components under irrigated and rainfed conditions in wheat (Triticum aestivum L.)

Summary Near-isogenic tall (no dwarfing gene), semidwarf (Rht1 or Rht2) and dwarf (Rht1 + Rht2 or Rht3) spring wheat lines were evaluated for yield and yield components under irrigated and rainfed conditions. Under irrigated conditions, the dwarf and the semidwarf lines exhibited a significant yield advantage over the tall lines. Under rainfed conditions, the semidwarf lines outyielded the tall as well as the dwarf lines. Percent yield reduction in response to drought stress was highest with the dwarfs and lowest with the tall lines. Dry matter production of the tall lines and that of the semidwarf lines did not differ significantly and both produced significantly more dry matter than the dwarf lines under irrigated as well as rainfed conditions. Plant height and kernel weight decreased with increasing degree of dwarfness while number of kernels per spikelet, harvest index and days to heading increased under both moisture regimes. The dwarfing genes did not have any significant influence on number of tillers/m² and spikelets per spike in either moisture regime.     

Phosphorus use efficiency in tall, semi-dwarf and dwarf near-isogenic lines of spring wheat

The impact of the Rht dwarfing genes on P utilization efficiency (PUTE = grain dry matter per kg P in above-ground biomass), total P uptake (Pt) and related traits was studied in the varietal backgrounds of two tall wheat cultivars, Maringa and Nainari 60. Four sets of near-isogenic lines carrying different combinations of the alleles Rht-B1b, Rht-D1b and Rht-B1c for gibberellin-insensitive dwarfism in the hexaploid wheat (Triticum aestivum L.) were compared with tall controls in two field trials under conditions of adequate nutrient supply and irrigation in Northwest Mexico. The yield-increasing effect of the dwarfing genes Rht-D1b and Rht-B1b led to improved PUTE in Maringa and total P uptake in both cultivars. Also, the double dwarf line of Maringa had larger grain yields and P uptake compared to the tall control. The Rht-B1c genotypes showed low PUTE, thick roots and high P concentration in vegetative biomass indicating a surplus of assimilates and P, which could not be translocated into the grains. A similar problem could be observed in Nainari 60 with Rht-B1b and Rht-D1b, which produced the largest grain dry matter with the lowest P concentrations in grains although they showed high P accumulation in straw. Most of the net P uptake occurred before anthesis. P absorption after anthesis was more critical for the dwarf genotypes. For double dwarfs and Rht-B1c, respectively, only 3% and 21% of the total accumulated P at maturity was absorbed at post-anthesis. The grain P of the dwarf lines came more from P accumulated at pre-anthesis and translocated from the vegetative biomass into the grain. The pre-anthesis P accumulation was positively correlated with spikes per m² (r = 0.91), whereas post-anthesis P accumulation correlated better with grains per spike(r = 0.72), and thousand kernel weight (r = 0.51). P uptake efficiency played a secondary role under these non-P-limiting conditions, and differences in root length density were only slightly affected by Rht-genes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Expression of late maturity α-amylase in wheat containing gibberellic acid insensitivity genes

Summary Two wheat cultivars, Spica and Lerma 52, which consistently produce high levels of -amylase during the later stages of grain development (late maturity -amylase), were crossed with a set of four near-isogenic lines carrying the tall (rht) allele or one of the dwarfing genes Rht1, Rht2 or Rht3 (GA-insensitive alleles). The F₁ and F₂ populations were developed and analysed for grain -amylase and plant height. The Rht3 gene exhibited the strongest influence on plant height and strongly inhibited new -amylase synthesis during the later part of grain ripening. By comparison, Rht1 and Rht2 had a less pronounced effect but still significantly reduced the expression of late maturity -amylase. These observations suggest that gibberellic acid is involved either directly or indirectly in this phenomenon. The implications of the effect of dwarfing genes on expression of late maturity -amylase are discussed in relation to cultivar improvement and to the identification and control of high -amylase germplasm.     

The effect of the ‘Golden Promise’ dwarfing gene on partial resistance to leaf rust and powdery mildew in spring barley

Summary F₂-plant progenies, derived from seven crosses between susceptible erectoides breeding lines and conventional, nutans breeding lines with partial resistance to leaf rust incited by Puccinia hordei Otth., derived from Vada x Cebada Capa, were examined in a field and a glasshouse experiment. In the field experiment, the nutans plant progenies generally were more resistant to leaf rust and powdery mildew than the erectoides progenies. In the glasshouse experiment, the components of partial resistance to leaf rust of six erectoides and six nutans progenies derived from one cross were studied. The nutans progenies generally had lower infection frequencies than erectoides progenies with a similar infection level in the field experiment. The variation for leaf rust and powdery mildew infection in the field was similar for the nutans and erectoides progenies. This suggests that erectoides lines with a fairly high level of partial resistance to leaf rust and powdery mildew can be selected from these populations.     

The inheritance of flower colour and vegetative characters in Rubus coreanus

Summary Dominant genes An ₁ for pink flower colour and Br ₁ and Br ₂ controlling branching of the canes in Rubus coreanus are described. In an F₁ progeny and in first backcrosses to red raspberry, some seedlings inherited the ability of R. coreanus to form up to three accessory buds per node. Polygenic systems controlling spine number and spine size are described, number and size being positively correlated. It is postulated that the greater size of spines of h (glabrous-caned) plants is due to linkage of a block of size-controlling genes with the H locus. The greater number of spines of H (hairy-caned) plants is attributed to a pleiotropic effect of the H allele. A new type of dwarf, cauli-flower, which occurred in the F₁ and some first backcross progenies, is described.     

桃树砧木的研究进展

文章综述了国内外桃树砧木的应用和研究进展情况,重点在抗根结线虫、耐涝性、耐旱性、耐盐碱性、抗根癌病、抗重茬、抗寒性以及矮化砧木的研究进展方面进行了综述。     

水稻显性矮秆新基因的RAPD分析

利用RAPD标记对中粳水稻新品种突变体Y98149中鉴定出的显性矮秆新基因进行研究。结果表明,在150对随机引物中,两对引物SAl530和SB930在亲本和近等基因池(均由10个高秆或矮秆植株组成)之间表现出多态性。用这两对引物对高秆和矮秆的F2群体的300个单株进行连锁分析,表明SAl530和SB930与新矮秆基因的连锁距离分别为15．3cM和9．3cM,两个RAPD标记位于同一侧。     

Analysis on the Dwarfing Genes in Zhepi 1 and Aizao 3： Two Dwarfing Gene Donors in Barley Breeding in China

Inheritance of plant height was studied in the two dwarfing gene donors, Zhepi 1 and Aizao 3, in barley breeding in China. Using direct cross and para-back-cross methods, allelic tests were carried out not only between the dwarfing genes in Zhepi 1 and Aizao 3, but also with br, uzu, denso, or sdwl and the six novel dwarfing genes that have been recently identified in barley in China. The results showed that the plant height was attributed to Mendelian inheritance of a recessive dwarfing gene both in Zhepi 1 and Aizao 3. The dwarfing genes carried by the two cultivars were the same, but different from the three known and the six novel dwarfing genes. On the basis of the present study, only two dwarfing genes have been used in barley breeding in China since 1950.