Thoughts and Practice on Some Problems about Research and Application of Two-Line Hybrid Rice

The main problems about research and application of two-line hybrid rice were reviewed, including the confusing nomenclature and male sterile lines classification, the unclear characteristics of photoperiod and temperature responses and the unsuitable site selection for male sterile line and hybrid dce seed production. In order to efficiently and accurately use dual-purpose genic male sterile lines, four types, including PTGMS （photo-thermo-sensitive genic male sterile rice）, TGMS （thermo-sensitive genic male sterile rice）, reverse PTGMS and reverse TGMS, were proposed. A new idea for explaining the mechanism of sterility in dual-purpose hybrid rice was proposed. The transition from sterile to fertile was involved in the cooperative regulation of major-effect sterile genes and photoperiod and/or temperature sensitive ones. The minor-effect genes with accumulative effect on sterility were important factors that affected the critical temperature of sterility transfer. In order to make better use of dual-purpose lines, the characterization of responses to photoperiod and temperature of PTGMS should be made and the identification method for the characterization of photoperiod and temperature responses of PTGMS should also be put forward. The optimal ecological site for seed production could be determined according to the historical climate data and the requirements for the meteorological conditions during the different periods of seed production.

Local Practices and Knowledge Associated with Date Palm Cultivation in Southeastern Niger

The date palm (Phoenix dactylifera L.), a dioecious species, is of particular interest in the Sahel due to its phenological plasticity in relation to climate change and its double-flowering capacity. This article explores local practices and knowledge associated with date palm cultivation in the oasis basins of southeastern Niger, and provides an inventory of local seed propagated varieties, for more effectively guiding agricultural research and the breeding of this species. We carried out a survey of 30 date palm growers in 14 villages of the Manga region. The qualitative data of the survey were processed by a Multiple Correspondence Analysis. We inventoried 19 date palm varieties, for which the main distinctive criterion was fruit colour, but some other criteria such as biology or provenance were also used. The cultural practices and knowledge associated with the date palm in Manga have improved since the 1990s. They also depend on ethnic groups and the importance they assign to farming compared to livestock rearing and trading activities. The type of basin (high, intermediate, or low water table) influences growers’ practices and perceptions. Lastly, the date harvest in the wet season is abundant, but of mediocre quality, whereas it is the opposite for the dry season harvest. To conclude, sustainable development of date palm cultivation in the Sahel zone relies firstly on the selection of varieties that are early fruit producers or that can complete fruit maturation during the raining season and secondly on technical capacity building for producers.