Development of reproductive structures in field peas (Pisum sativumL.) at different densities

Abstract

Two field pea cultivars, Huka and Whero, were grown under dryland conditions in Canterbury, New Zealand, at 5 plant densities ranging from 25 to 163 plants/m-. Retention of flowers and pods and development of ovule initials were investigated. Flowers per plant, pods per plant, ovule initials per pod, peas per pod, and the area of photosynthetically active tissue per plant (plant area) were aß inversely related to plant density. Although Huka produced more flowers, pods, and ovule initials than Whero, Whero had the greater plant area and lost fewer of these structures. This may be related to Whero's ability to maintain a higher photosynthetic area per reproductive structure. During pod filling the topsoll moisture content was low but water was available at greater depths. Plant area and plant area index had a greater effect on the retention and development of reproductive structures, especially ovule initials, than did soll moisture. Further work is required into the role of other plant and environmental factors on the development offlowers, pods, and ovules. Losses ofreproductive structures could be reduced by a combination of plant breeding and improved agronomy.

English Pea (Pisum sativum) Tolerance to Paraquat and Paraquat Plus Bentazon

“…Weeds reduce pea branching, leading to pod abortion and decreased yields (Falloon and White 1980;Lawson 1982;Nelson and Nylund 1962;Procter 1972). Lawson (1982) reported yield losses due to weeds of 8 to 140/0 in vining peas grown over a range of crop densities from 50 to 100 plants/m 2 • Reductions of this magnitude were equivalent to a loss of 10 to 31 plants/n1 2 • McCue and Minotti (1979) found that season-long weed competition reduced pea yields 30% compared to weed-free controls.…”