Abstract:

To solve the problems of long-term abandonment of a large amount of understory land in China, overgrowth of weeds, serious pests and diseases, and forest fruit quality declining year by year, the foxtail millet germplasm resources which have good comprehensive traits and certain utilization value were used as experimental materials in this study. Through specialized experiments, the germplasm resources with certain shade tolerance traits were identified and screened, the shade-tolerant parent materials were created, and the shade-tolerant foxtail millet hybrids were then created to meet the needs of stereo interplanting of foxtail millet and forest tree. The physiological mechanism of shade tolerance of shade-tolerant foxtail millet hybrids and parent materials was studied by measuring the contents of chlorophyll a and chlorophyll b in leaves, their ratio and the number of root wheels. The main results were as follows. (1) Seven shade-tolerant sterile lines and four shade-tolerant restorer lines were created. (2) Eight shade-tolerant foxtail millet hybrids were created. (3) The physiological mechanism of shade tolerance of these materials lay in that the contents of chlorophyll a and chlorophyll b were both high, which was 2.11-2.35 mg/gFW and 0.65-0.76 mg/gFW, respectively; the value of chlorophyll a/chlorophyll b was low, ranging from 3.09 to 3.25; the number of root wheels was equal or greater than five, and they could absorb more nutrients from the soil; they had strong resistance and tolerance to pests and diseases in shaded environment. The breeding of shade-tolerant foxtail millet hybrids supported the development of understory economy, and established four stereo interplanting models, foxtail millet/chestnut, foxtail millet/walnut, foxtail millet/hawthorn and foxtail millet/medium and low density-ecological forest.

Key words: shade tolerance, foxtail millet, hybrid, germplasm innovation, physiological mechanism