Early-season growth in relation to region of domestication, seed size, and leaf traits in common bean uri icon

abstract

  • In common bean (Phaseolus vulgaris L.) large-seeded lines (which are predominately of Andean background) have a smaller relative growth rate (RGR) during early season growth (up to 30 days after sowing) than do lines with small seed size (which are predominately of Mesoamerican background). Growth analyses, single-leaf gas exchange, and internal leaf anatomy were studied during vegetative growth for 16 lines of common bean (9 Andean and 7 Mesoamerican) at Palmira and Popayan, Colombia, and for 14 Lines at Gainesville, Florida, to determine the basis for the smaller RGR of large-seeded Andean lines. Pooled analyses across sites revealed that RGR, net assimilation rate (NAR), single-leaf carbon exchange rates (CER), specific leaf weight (SLW), specific leaf N (SLN), leaf thickness, and mesophyll-cell surface area per unit leaf area (A(m)/A) exposed to air were all smaller for large-seeded Andean lines than for small-seeded Mesoamerican lines. Relative growth rate was positively correlated (P < 0.10) with CER at all three sites. We postulate that the smaller RGR of the large-seeded Andean lines is a function of their slower CER, which result from thinner leaves with less photosynthetic apparatus per unit leaf area.

publication date

  • 1997
  • 1997