Seasonal variation in the dynamic growth and development traits of peanut lines

Abstract

Physiological traits responsible for differences in yield performance among pre-released genotypes are normally not known. The objective of the present study was to evaluate seasonal variations in dynamic growth and development traits between 12 large-seeded Virginia-type and 14 small-seeded Spanish-type advanced breeding lines of peanut (Arachis hypogaea L.). The experiment was conducted in 1999 and 2000 at Khon Kaen University in Northeast Thailand for three planting dates, representing the early-rainy season, mid-rainy season and dry season. Very similar phenological development was observed for all lines within each group and between the early and the mid-rainy seasons. However, a lower temperature during the early growth stage in the dry season delayed flower initiation and extended maturity. During this period, crop growth rates as well as the development rate for leaf area index and specific leaf area were also lower compared with the rainy seasons. On average, both pod yield and total biomass for the rainy season and the dry season were about the same. Variations among lines within each group were also small. For these advanced breeding lines, the pod growth rate was the most important yield determinant while the crop growth rate had lesser effect and the partitioning coefficient and pod-filling duration had no significant effect. However, the crop growth rate, pod growth rate and partitioning coefficient were important traits for a line to be the top yielder. Pod-filling duration was also important when the lines involved were considerably diverse in maturity and seed size. Information on these traits, if used together with final pod yield, will make varietal selection more efficient.

Genotypic Differences in Current Peanut (Arachis hypogaea L.) Cultivars in Phenology and Stability of These Traits under Different Irrigation Scheduling Methods

“…Overall, the pattern and magnitude of LAI measurements across the season in this study were typical for other peanut cultivars (Banterng et al, 2003;Kiniry et al, 2005), but some studies have documented a more parabolic pattern for LAI development (Kar and Kumar, 2007) as well. Patterns of growth in the current study indicated that late-maturing cultivars had higher late-season growth than mid-maturing cultivars.…”

“…Although an early study indicated that peanut yield was determined more by genetic pedigree than growth habit (Norden and Lipscomb, 1974) more recent studies show a strong link between growth and reproduction for other legumes (Krishnamurthy et al, 1999) and other peanut culitvars (Bennett et al, 1993;Banterng et al, 2003). In the current study, traits relating to canopy development (and thus assimilation capacity) as well as mid-season reproductive potential appeared to be causally linked to final reproductive output in the late season.…”

“…Despite expectations of a kind of genetic dilution to phenotype variability among cultivars, genotype differences were quite strong for growth traits. Previously documented cultivar differences in leaf weight and harvest index do exist, but again these were in widely diverse botanical types (Bell et al, 1993a;Craufurd et al, 2002;Banterng et al, 2003), making the current study's documentation of growth variability among closely related cultivars unique. Although year had a significant effect on these traits indicating an effect of climate on peanut physiology, there were largely no interactions between year and genotype indicating that the changes caused by climate were relatively low in magnitude and did not alter the overall genetic pattern of development for each cultivar.…”

“…For crop modelers, knowledge of how cultivars can differ in their growth and reproductive responses can be essential (Hammer et al, 1995). Previous work has shown that there is variability in growth and reproduction in peanut but comparisons have typically been made among widely different peanut species and botanical types (Bell et al, 1991a,b;Bell et al, 1993a,b;Bell et al, 1994;Craufurd et al, 2002;Banterng et al, 2003). But the existence of variability among current peanut cultivars whose genetic pedigrees have become increasingly similar due to the type of traits that have been favored for several years is questionable at best.…”

“…Biomass partitioning especially between leaves and stems or between vegetative and reproductive traits can vary among cultivars in other legumes such as cowpea (Vigna unguiculata (L.) Walp.) and chickpea (Cicer arietinum L.), and some diversely related peanut cultivars (Bell et al, 1993b;Bell et al, 1994;Krishnamurthy et al, 1999;Banterng et al, 2003;San José et al, 2004). Unlike growth traits, the separation among cultivars in reproductive traits was not related to maturity class.…”