热激处理对柰李果实贮藏品质的影响

热激处理可用于控制采后果实的病害、腐烂及后熟.对不同温度与时间组合的热激处理与柰李低温贮藏品质之间的关系进行研究.结果表明,40℃、4 h的热激处理对提高柰李抗冷性和保持柰李贮藏品质的效果较好.     

Frost tolerance in wild potato species: Assessing the predictivity of taxonomic, geographic, and ecological factors

The use of genetic resources could be more effective and efficient if we were able to predict the presence or absence of useful traits in different populations or accessions. We analyzed the extent to which taxonomic, geographic and ecological factors can predict the presence of frost tolerance in wild potatoes. We used screening data for 1646 samples from 87 species that had been collected in 12 countries in the Americas. There was a strong association of frost tolerance with species and to a lesser extent with taxonomic series. There was significant geographic clustering of areas with wild potatoes with similar levels of frost tolerance. Areas with a high level of frost tolerance are the central and southern Peruvian Andes, the lowlands of Argentina and adjacent areas, and a small area in the central Chilean Andes. There is a greater chance of finding wild potatoes with high levels of frost tolerance in areas with a yearly mean minimum temperature below 3 ^°C than there is in warmer areas. However, temperature is only a weak predictor of frost tolerance. Temperature data alone did not predict observed frost tolerance in eastern Argentina/Uruguay and falsely predicted it in the southwestern United States. Because many wild potato species occur over small areas, taxonomic, ecological, and geographical factors are difficult to disentangle. This revised version was published online in July 2006 with corrections to the Cover Date.     

Amino Acid Resources of the Wild Relative of Barley (Hordeum spontaneum) in Israel

Measurements were made on amino acid contents in collection of wild barley (Hordeum spontaneum)., grown in pot conditions, and in some Israeli breeding lines and cultivars of Hordeum vulgare. H. spontaneum was low in lysine content and high in prolilne plus glutamic acid compared to H. vulgare. Lysine content was positively correlated, in H. spontaneum, to all other ammo acids except proline and giutamic acid. Inter-populanon rnean differences for Iv-saie in H. spontaneum were small and lysine variation was obscured due to variation in protein content. The use of H. spomancum in breeding high protein. nutritionally improved barley is discussed.     

Tolerance of Triticum Species to Aluminum*

A total of 523 accessions of 25 Triticum species were screened for tolerance of aluminum in solution. Only 22 accessions were identified with some root re growth following exposure w culture solutions containing 12 ppm aluminum. Interestingly, 15 of these 22 accessions were species with the Un genome (T. uniaristatum). The level of aluminum tolerance of none of these 22 accessions is as high as that of the cultivar ‘Atlas 66’.     

Natural triploid hybrids between Solanum acauleBitter and S. infundibuliformePhilippi in the province of Jujuy,Argentina

Summary The occurrence of natural triploid hybrids between tetraploid Solanum acauleBitter subsp. acaule and diploid S. infundibuliformePhilippi both tuber-bearing Solanums, in the Puna region of Jujuy, is reported. The natural hybrids, which are morphologically intermediate between their putative parents and completely male sterile, have a somatic chromosome number of 36. The artificial hybrids, obtained by crossing both parental species, closely resemble the natural ones thereby confirming their parentage. It is proposed to designate the natural hybrids Solanum x viirsooi hybr. nov.     

Responses of Israeli wild emmers to selected Australian pathotypes of Puccinia species

Summary Seedling responses to one Australian isolate of each of the stripe rust, stem rust and leaf rust pathogens were determined for 541 accessions of T. dicoccoides collected from 23 locations in Israel. Resistance to stripe rust was more frequent than resistance to stem rust. Stripe rust responses showed a wide range of variability indicative of a number of genes for resistance. Comparison of the present stem rust data and that reported for the same accessions tested in Israel indicated that different genes were operating in each country. Only moderately resistant responses to stem rust were obtained. This level of resistance is probably inadequate for transfer to commercial wheat cultivars. We found no potentially useful seedling resistance to leaf rust.     

Effect of seed coat color on seed dormancy in different environments

Arachis glabrata Benth, variety glabrata coll. GK 10596 (PI 276233; ICG8176) belonging to section Rhizomatosae has multiple disease resistance. Fertile hybrids between A. hypogaea L. and A. glabrata, A. duranensis Krapov & W.C. Gregory and A. glabrata and A. diogoi Hoehne and A. glabrata were produced. Introgression of DNA from A. glabrata into A. hypogaea, A. duranensis and A. diogoi was analyzed by isozyme and RAPD analyses. Hybrids were backcrossed and BC₁ seeds were obtained in all the three hybrids. Hybrids were evaluated for the transfer of disease resistance genes from A. glabrata, which was confirmed. RAPD analysis with several primers showed that DNA fragment pattern were not simply represented, instead there were new bands and several parental bands were absent in the interspecific derivatives. This revised version was published online in August 2006 with corrections to the Cover Date.     

Genetic variability for seed oil content and seed index in some wild species and perennial races of cotton

A 3‐year study was made on genetic variability of seed oil content and seed index with 20 wild species, two cultivated species and six perennial races of Gossypium arboreum cotton maintained at the Central Institute for Cotton Research, Nagpur, India. The mean seed oil content varied from 10.26 to 22.89% in 22 species of Gossypium and six races of G. arboreum. In this material the weight of delinted seed varied from 43.33 to 54.54 mg/seed. The highest seed oil content was recorded in the species G. lobatum followed by G. harknessii. On average, for both traits, the means were higher for G. arboreum and its races. However, G. africanum and G. harknessii reached the level of G. arboreum and its races for seed weight, while five wild species surpassed the best races and G. arboreum in seed oil content, among them was G. harknessii. To breed simultaneously for seed oil content and seed weight, crosses between races of G. arboreum and wild species of Gossypium seem to be promising.     

A new cytoplasmic male sterility source from wild Helianthus annuus

Summary A new cms source, ANN-5, was found in wild Helianthus annuus. This source showed high stability under different conditions in 1991 and 1992. All progenies from crosses of this source with several stable B-lines and restorer lines, which are homozygous for the gene which restores Leclercq's source of male sterility, were completely male sterile. Flower contained pistils and atrophied stamens. The cytological analysis showed that pollen mother cell degeneration took place in a premeiotic stage.     

Comparative fine mapping of fruit quality QTLs on chromosome 4 introgressions derived from two wild tomato species

Despite their unsuitability for agricultural production, the wild relatives of crop species represent a largely untapped resource of novel QTLs potentially useful for crop plant improvement. In this regard, previous introgression studies, involving several different wild tomato species, have shown that the long arm of chromosome 4 contains QTLs for many horticulturally important traits including soluble solids content, fruit shape, lycopene content and biochemical composition. However, these earlier studies were unable to determine how many genes control these traits and whether genes affecting the same character from different wild species are allelic or not. In an effort to shed light on these issues,we have constructed a series of lines containing small, overlapping introgressions for portions of the long arm of chromosome 4 from L. peruvianum and L. hirsutum and tested these lines in replicated field trials. The results provide evidence for multiple, non-allelic loci controlling soluble solids and fruit weight. They also show that the loci controlling some traits (e.g. fruit shape, fruit weight, epidermal reticulation) co-localize to the same portions of chromosome 4, a result that maybe attributed to pleiotropy and/or gene dense areas with lower than average recombination. The implications of these finding for molecular breeding and utilization of exotic germplasm are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.