Northeast Yunnan Research Articles

Microsatellite analysis of landrace rice core collection in Yunnan, China

The distribution of genetic diversity between Oryza sativa L. ssp. indica and O. sativa L. ssp. japonica covering different ecological zones in Yunnan was studied, and specific markers of indica / japonica subspecies, paddy/upland rice and different ecological zones were screened, using 36 microsatellite primers and 113 accessions in the Yunnan landrace rice core collection. The genetic diversity of japonica was higher than that of indica , and the ecological zone with the highest and smallest genetic diversity lay in south-east and north-east Yunnan, respectively. This distribution was consistent at morphological and isozyme levels with studies on the entire Yunnan rice resources and core collection. In addition, the results showed that, among 416 markers, there were six indica / japonica -specific markers, 15 specific markers for paddy/upland rice and three specific markers in different ecological zones. The main conclusions are that the landrace rice core collection in Yunnan genetically represents the entire landrace rice resources in Yunnan, the centre of genetic diversity at DNA level lies in south-east Yunnan, and the DNA differentiation between indica and japonica is small. Furthermore, microsatellite markers were useful for studying the genetic diversity, classification and ecotype of germplasm resources and their core collection.

An analysis of interspecific associations of Pinus squamata with other dominant woody species in community succession

Pinus squamata is an extremely endangered pine from northeast Yunnan Province of China, which was reported from only one locality where there are 32 individuals in the field. In order to analyze its ecological relationships with other trees and shrubs, a series of techniques, including analysis of variance, χ2 test and percentage of co-occurrence, were used to analyze interspecific associations of dominant woody species in communities with P. squamata. The results indicated significantly positive correlation of the association of overall woody species in the two communities with P. squamata. There is also significantly positive correlation in the community on the north facing slope, but only a positive correlation in the community on the south-west facing slope. Considering that the community on the south-west facing slope is mixed coniferous and broad-leaved forest and that on the north facing slope is evergreen broad-leaved forest, the results imply that the communities with P. squamata may be in succession from mixed coniferous and broad-leaved forest to evergreen broad-leaved forest. Combined with the data of χ2 test and percentage of co-occurrence, we conclude that P. squamata has no significant correlation with other woody species, and its co-occurrence with other trees may be by chance. Finally, its requirements for survival may be threatened by evergreen broad-leaved woody species.

REVISION OF THE GENUS MALAISIUS ARROW (COLEOPTERA: SCARABAEIDAE: MELOLONTHINAE)

AbstractThe rhizotrogine genus Malaisius Arrow is revised with descriptions of two new species, M. siamensis from northern montane areas of Thailand, and M. similis from northeast Yunnan, China. The type species, M. mollis Arrow, is redescribed, and Malaisius yunnanus (Moser) (Cyphochilus) is proposed as a new combination. The female of Malaisius is described for the first time and a key to the male species of Malaisius is provided. A discussion of relationships and distinguishing characters of the closely related genera Cyphochilus Waterhouse, Dedalopterus Sabatinelli and Pontuale, and Malaisius is also given.

Devonian calcrete from China: its significance as the first Devonian calcrete from Asia

The first Devonian calcrete known from Asia has been found in northeast Yunnan Province in southeastern China. The scarcity of lower and middle Paleozoic calcretes and their paleoclimatic significance prompt this brief note.