Chromosome constitution of species in the plant genus Chaenomeles

The chromosome number was studied in plants, derived from seeds collected in the wild, of all four species (C. cathayensis, C. japonica, C. speciosa and C. thibetica) presently recognised in the genus Chaenomeles Lindl. (Maloideae, Rosaceae). For the first time the chromosome number of C. thibetica was also determined. Chaenomeles thibetica was diploid and had a chromosome number of 2n = 34. The results of chromosome counting in the three other species were in agreement with the literature. Thus, all species within the genus Chaenomeles were confirmed to be diploid and to have the same chromosome number, 2n = 34

Breeding strategies for the fruit crop Japanese quince (Chaenomeles japonica)

In this paper, an ideotype for the fruit crop Japanese quince (Chaenomeles japonica) is established and traits to be specifically considered for selection and breeding are discussed: adaptation and hardiness, disease resistance, thorns, suckering, growth, rooting, time of ripening, yield, amenability for mechanical harvesting and fruit quality. In addition, test guidelines and descriptors for Chaenomeles species are presented. Short-term and long-term breeding strategies are suggested, based on a study of general and specific combining ability for plant vegetative traits, fruit yield and morphology traits, and fruit biochemistry traits. An efficient breeding strategy for Japanese quince could be based on recurrent selection. However, extensive test crosses and progeny tests in well-designed field trials should also be considered since some important traits are controlled by additive as well as non-additive genes

Growth and Phenology of Hybrid Aspen Clones (Populus Tremula L. X Populus Tremuloides Michx.)

Height, basal diameter, diameter at breast height, bud burst, and leaf development were recorded in a 5-year-old hybrid aspen clonal trial. The field trial consisted of four aspen hybrid clones (Populus tremula x Populus tremuloides) and one local P. tremula seedling source. Phenological traits were observed in the 3rd year. Growth patterns were recorded during the 3rd and 4th years. Phenological traits were explored in relation to hybrid vigor expressed as growth traits. Differences were observed for phenological and growth traits among hybrid clones and P. tremula. The growth period varied from 143–158 days for the four hybrid clones, and was 112 days for P. tremula. The correlation between growth period and yield was highly significant. The annual growth rate of height for the hybrids was 4.2 cm per 7 days (2.4 for P. tremula) in the 3rd year and 6.4 cm per 7 days (2.9 for P. tremula) in the 4th year. After 5 years, mean estimated stem volume of the hybrids was 3.9 times that of P. tremula. Significant clone by year interaction was observed for height, diameter, and volume growth. The hybrid vigor seems to be mainly attributable to a longer growth period.</ja:p

Promoting the conservation and use of plant genetic resources by training and research: capabilities and capacities for plant genetic resources training in public universities and institutions in Eastern Africa

In the mid 1990s, it was realized that the plant genetic resources training approach through the provision of fellowships, and sponsoring of national and regional thematic training courses by IPGRI and other partners was not sustainable. This acknowledgement stimulated the need to search for an alternative and more sustainable approach. The involvement of local institutions spearheaded by the universities was identified as more appropriate. The involvement of the universities clearly fits into IPGRI's global training and capacity building efforts. It provides a window to sustainability and involvement of all the relevant national institutions in contributing to plant genetic resources training activities at the national and regional levels. This report is the result of visits made in the year 2000 to designated universities, institutes and organizations in Ethiopia, Kenya and Uganda to carry out a survey and gather such information. The document details information on capabilities relevant to PGR training within and among institutions. It particularly pays attention to the institutional capabilities; institutional capacities; and the model (institutional) links that are basic for setting up a consortium of stakeholders, not as individual persons but as communities of educators with a common vision and mission. The proposition for a consortium is an excellent one as it calls on country partners to participate by the comparative advantages each of their institutions possess. The ownership of the EAPGRTC is thus made participatory rather than centre-managed.The document finally recommends levels of training that can immediately be offered in an EAPGRTC context. It also identifies gaps observed on the ground and suggests ways to address them. The report further deliberates on the way forward as well as setting priorities for strengthening such a consortium so as to meet future PGR training and research needs in the East African region. The document should be useful in crystallizing a consortium initiative