Optimizing the Airflow Velocity Combinations Acting on Male Parent Rows for Hybrid Rice Pollination

Abstract

Highlights The effect of airflow velocity on pollen distribution was investigated under a large-scale planting mode. The response surface model between pollen distribution and airflow velocity was constructed. Multi-objective optimization of airflow velocity combinations was carried out using a genetic algorithm. The optimal airflow velocity ranges of the male parents are from 22.4 to 24 m/s, 23.1 to 27 m/s, and 23.5 to 24.1 m/s. Abstract. Pollination is the key link in hybrid rice seed production. The pneumatic pollination method can significantly improve pollination efficiency under large-scale planting mode. To investigate the effect of airflow velocity on pollen distribution in hybrid rice pollination, the velocities of airflow acting on different male parent rows were taken as the experimental factors. The pollen amount in per view and the variation rate of pollen distribution in female parent rows were used as experimental indices. Field experiments were carried out using a self-made pneumatic pollination experimental platform. The results showed that when the airflow acted on the male parents in the first and second rows of the adjacent female parent, the pollen dissemination distance was short when the airflow velocity was low, and the pollen was mainly deposited in the area near the male parents. With the increase in airflow velocity, the peak pollen amount in per view in the female parent rows gradually moved away from the male parent rows. But they are all in the female parent rows of the effective area. The total amount of pollen also increased. Due to the blocking effect of the outer male parent row, the pollen dissemination was restricted when the airflow alone acted on the third male parent row. The effect of airflow velocity on pollen distribution was not obvious. The experimental results of different airflow velocities acting on the parent row alone are used as the basis. The objective functions of pollen amount, distribution variation rate, and airflow velocities of each male parent row were established by response surface methodology. The multi-objective optimization of airflow velocity combinations was carried out by a genetic algorithm. The pollen distribution under different air velocity combinations was obtained. When the optimal airflow velocity ranges of the male parents in rows 1, 2, and 3 are 22.4 to 24 m/s, 23.1 to 27 m/s, and 23.5 to 24.1 m/s, respectively, pollination is uniform and sufficient. The research results can provide a basis for the development of pneumatic pollinators and the optimization of working parameters under large-scale planting mode. Keywords: Multi-objective parameter optimization, Pneumatic pollination machinery, Response surface modeling, Rice pollination.