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Growth and yield relationships in the garden pea (Pisum stivum L.)

University of British Columbia

Recently developed methods of growth and yield analysis were applied to the results of a field experiment to determine (i) the effect of seed inoculation on the growth and yield of two cultivairs of garden pea (Pisum sativum L.) - 'Dark Skin Perfection' (DSP) and 'Early Frosty' (EF), (ii) the physiological basis for yield variability and (iii) the dynamics of reproductive growth in the pea. Seed inoculation had no noticeable effect on yield. There were, however, significant cultivar differences--DSP was larger, matured later but had lower yields than EF. Growth analysis revealed that these differences were due to the extended vegetative growth phase, higher leaf area ratio and lower harvest index of DSP. Further analysis indicated that EF had a more efficient growth strategy, as the maximum rate of partitioning of dry matter into the reproductive structures coincided with high leaf activity. By contrast maximum sink activity in DSP occurred during leaf senescence. Stem length, average leaf area and inverse leaf weight ratio were the main components of biomass variability. Yield variation, however, was affected indirectly by stem length, average leaf area, reproductive effort and average seed weight, and directly by the number of nodes, pod set and inverse leaf weight ratio. These results imply that the supply of photosynthetic material is important for increased pea yields. Significant negative correlations between vegetative components and average seed weight suggest compensation and competition between these components. Thus, yield improvement may be attainable by (1) enhancing the component which is unaffected by this compensation or (2) reducing the competition by shifting the equilibrium. Two crucial periods when source supply may affect yield were detected during the reproductive phase. The first period (61 days after planting in DSP and 55 days after planting in EF) was more pronounced in DSP. In the second phase (day 75 for DSP and 65 for EF) seed growth became important and seemed to influence leaf activity. This finding suggests that the rate of canopy establishment is as important as the rate of pod filling for improving yields. A dynamic model simulating pod yield in relation to source supply is outlined.

Text

2010-06-16

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http://hdl.handle.net/2429/25794

Plant Science

University of British Columbia

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