Shade Effects on Growth, Partitioning, and Yield Components of Peanuts¹

Abstract

Peanut (Arachis hypogaea L.) may have one or more periods during development when low solar radiation intensity is particularly detrimental to high yield. The present studies were conducted in the field to determine the effect of shade on vegetative growth, partitioning of assimilates and yield components of peanut. In a 2‐year experiment, 75% shade was applied for 7, 10, 14, or 21 day periods during flowering, pegging, podding, and maturing phases. The objective was to determine which reproductive phase was most sensitive to low solar radiation intensity. Flower number, peg development, pod formation, and dry matter accumulation and partitioning were measured at regular sampling intervals. Shade during the peak flowering period reduced the number of flowers per plant and inhibited peg formation. Shade during the pegging and podding phases reduced total peg and pod number and reduced pod dry weight. Shade during the maturing phase reduced seed fill as shown by reduced shelling percentage and a lower number of fruits achieving mature pod status. On the average, over all stages, 75% reduction of light intensity decreased the growth rate of vegetative parts by 85%, the reproductive growth rate by 67%, and the total biomass growth rate by 67%. Shade prior to podding increased partitioning to vegetative growth, by 20%, whereas shade during the podding phase (83 to 104 days) increased dry matter partitioning to pods by 127%. Seventy‐five percent reduction in solar radiation intensity reduced yield of Florunner peanuts significantly only when the duration was for 14 or 21 day periods. Podding was the phase in which yield was most sensitive to shade with a 30% reduction in fruit yield from shade during 83 to 104 days of age. The maturing phase was next in sensitivity to shade, which decreased yield primarily by decreasing seed fill in existing fruits. Twenty‐one days of shade at flowering did not reduce final fruit yield, since the plants had time to recover from the loss of active flowers and subsequently bear flowers and produce a normal pod load.

Shade Effects on Phaseolus vulgaris L. Intercropped with Zea mays L. under Well‐Watered Conditions

“…1972). Several studies have showed shade effects on growth and yield of legume crops: a decrease in biomass/yield and an increase in plant height with an increase in radiation reduction (Hang et al. 1984, Stirling et al.…”

“…Environmental factors, including light and water, can produce variation in plant growth, and this variation is greater than genetic differences (Bowes et al 1972). Several studies have showed shade effects on growth and yield of legume crops: a decrease in biomass/yield and an increase in plant height with an increase in radiation reduction (Hang et al 1984, Stirling et al 1990). As regards photosynthetic organs, shading results in thinner leaves, and therefore a decrease (or an increase) in specific leaf weight (or specific leaf area) (Bowes et al 1972, Crookston et al 1975, Stirling et al 1990).…”

The Effects of Stress on Reproductive Characters of Lobelia Cardinalis

“…Environmental variation commonly influences seed yield, either indirectly by affecting growth and flower production (Harper 1977, Grimes 1979, Marshall et al 1985, Vasek et al 1987 or directly through seed and fruit abortion (Early et al 196 7, Claassen and Shaw 1970, Pepper and Prine 1972, Herrero and Johnson 1981, Hong et al 1984, Marshall and Ellstrand 1986. It also influences nectar production (Fahn 1949, Pedersen 1953, Bertsch 1983, Pleasants 1983.…”

Growth of Bean Strip‐Intercropped with Maize: Evaluation of the CROPGRO Model

“…However, canopy volume (height × width in m 3 ) for both sowing dates significantly increased by around 40% in the Rows 2 and 5 compared to the average bush bean canopy volume in Row 1 and the monocropped bush bean. The increase in canopy height and width in Rows 2 and 5 likely resulted from a shade‐induced elongation of internodes and petioles as a general strategy of plants to intercept more light (Vandenbussche et al, 2005) as reported in numerous studies (e.g., Cox, 1978; Hang et al, 1984; Gardiner and Craker, 1981; Smith and Whitelam, 1997; Jurik and Van, 2004).…”