| dc.description.abstract | The study was conducted at the University of Nairobi
Facul ty of Agr icul ture Farm, Kabete, located on la ti tude 10 5 I
south and longitude 36° 44 I east at an altir.ude of about 1800
metres above sea level. The study investigated the following
physiological crop parameters: leaf net photosynthetic rates,
leaf nitrogen, specific leaf weight, leaf area indices and stem
non-structural carbohydrate contents. Plant biomass
accumulation was also determined. These parameters were taken
at fortnight ly intervals from
(f lower ing phase of growth)
32 days after
t i 11 ma t u r i t Y
emergence
in ten
(DAE)
bean
(phaseulus vulgaris L.) cultivars namely: Pocho, GLP-92, White
Har i cot., GLP-1004, GLP-2, GLP-24, Ulonzo, E-l, E--3 and E-5.
The study was done in .two different seasons; with the first
season experiment (experiment 1) running from 29th March, 1994
to 8th of July 1994. Second season experiment (exper imen t I I)
was conducted from 12th of October 1994 to 10th of January,
1995.
The results of the study revealed a variation of the above
mentioned physiological parameters among cul ti vars. Leaf net
photosynthetic rate and leaf nitrogen contents had a positi ve
correlation at 45 DAE (pod set). There was also positive
correlation between photosynthetic rates and yields. These
parameters
differences
were however not the best indices for yield
among cultivars since even higher yielding
cultivars such as Pocho, E-l, E-3, and E-5 had relatively lower
performance in these characters. Non-structural carbohydrate
remobilization from the stem contents at pod set about 45
DAE) seemed to be a good indicator for yield differences among
bean cultivars. Specific leaf weight variation was more stable
as a result of environmental changes and therefore was proposed
a good index for the basis of yield differences among
cultivars. Harvest index (HI), apparent harvest index (AHI) in
this case, was also promising indicator of yield differences | en |
