Indigenous Cultivars Research Articles

CHESTNUT PRODUCTION IN CHINA: A MODEL FOR DEVELOPMENT OF A CHESTNUT INDUSTRY IN THE SOUTHEASTERN U. S.

The Chinese chestnut (Castanea mollissima) has been cultivated in China for more than 1000 years. During this period, indigenous cultivars and traditional cultivation practices have been used. China is the leading producer of Chinese chestnut (Castanea mollissima) with 37% of the world' s production. In the last 4 years, improved cultivars and improved cultural practices have resulted in marked increases in production. The leading provinces in Chestnut production are Hopei, Hubei, and Shandong. Severe injury, crop losses and tree mortality have resulted from the chestnut gall wasp in China Yields have increased greatly in Hubei province through cooperative breeding and developmental research between the Department of Horticulture Auburn University and the Hubei Academy of Agricultural Sciences. Two resistant seedlings from Auburn University are being utilized to save the chestnut industry in China and possibly worldwide.

BREEDING MELONS FOR DISEASE IN CHINA

The watermelon has been cultivated in China for more than 1000 years. During most of this period, indigenous cultivars and traditional cultivation practices were used. In the last decade, many improved cultivars have been developed and the use of plastic mulch and other improved cultural practices have been utilized. China has become the largest producer of watermelons with the production area increasing to 1 million hectares and 15 million tons in 1988. Watermelons are grown in almost all production areas of China. The production areas are: the Northwest inland dry region, the North China plain region, and the Changjiang (Yantzi river) valley rainy region. Severe injury and crop losses occur from Fusarium wilt, (Fusarium oxysporium v. niveum) anthracnose (Colletotrichum laginarium), and gummy stem blight (Didymella bryonaea). Cooperative breeding and developmental work was initiated between the Dept. of Horticulture, Auburn University and the Hubei Academy of Aggricultural Science and the Hubei Agricultural College, Jing Zhou to evaluate cultivar and germplasm and to develop multiple disease resistant melons that produce high yields of excellent quality fruit.

Physiology of Growth and Yield of Bread Wheat (Triticum aestivum L.): A Comparison of Indigenous and Exotic Cultivars of Saudi Arabia

Physiology of Growth and Yield of Bread Wheat (Triticum aestivum L.): A Comparison of Indigenous and Exotic Cultivars of Saudi Arabia

Population-genetic structure and optimal sampling of land races of barley from Iran

Allozyme variation at 25 genetic loci was assayed in twelve indigenous cultivars (land races) of barley from Iran. For these loci the average probability that two gametes drawn at random from one population would differ at a locus was 0.082. In the collection as a whole, this measure of genetic diversity was 0.161, so that about half the total diversity was distributed between populations. Of the total of 31 allozyme variants, about half were common (frequency >0.10) in only one or two regions. The results were compared with diversity estimates based on spike morphological polymorphisms; with allozyme polymorphism in two composite crosses (CC21 and CC34) of cultivated barley; and with previous results for allozyme polymorphism in Israel populations of wild barley. In the land race samples, the diversity of spike types was a poor index of allozyme diversity. The total allozyme diversity in this collection of land races was intermediate between the moderate levels in composite crosses and the high levels in Hordeum spontaneum from Israel. These results emphasize the role of land races as valuable genetic resources for plant breeding. They support sampling strategies which, by taking samples of moderate size from many sites, emphasize the collection of locally common alleles, as against strategies framed to capture the rare, conspicuous morphological variant by intensive or biased sampling, or strategies based on collecting the extreme ecotypes from a cline. The chromosomal location of 20 of the allozyme loci as deduced from wheat-barley addition lines, is listed in the appendix.

Screening of Rice Cultivars for Resistance to the Brown Planthopper, Nilaparvata lugens Stal., by Three Biotypes

To identify rice cultivars resistant to the brown planthopper, Nilaparvata lugens Stal., 2, 904 introductions of indigenous cultivars and breeding lines and 383 domestic, mostly old indigenous, cultivars were screened by the bulk seedling method with biotype I(wild type) of the insect. Except for the breeding lines most of the resistant indigenous cultivars were found to originate from Sri Lanka and southern India. While only a fer originated from northern India, Burma and Thailand. Tolerant but not resistant cultivars distributed rather widely within Asia, while almost no one was detected in Europe, Africa, America and Australia. Biotype groups II and III of the brown planthopper, selected through rearing on the resistant cultivars, were found to be effective folestimating the genotypes of resistant cultivars. A total of 120 cultivars were classified according to their pattern of biotype reactions. About 60 per cent of the Sri Lanka cultivars were found to possess the resistance gene bph 2, in contrast with only 10 per cent among the Indian cultivars.

Solanum peloquinianum: A new wild potato species from the Peruvian Andes

After having collected a vast amount of indigenous potato cultivars, The International Potato Center has recently intensified its explorations in the Andes of South America. The intent is to collect and utilize in its breeding programs the diversity of wild species that are found profusely distributed in the mountainous regions of South America. During the course of this work, several new species are being identified. Following we present a diploid species which is new to science.