| dc.description.abstract | Barley (Hordeum Valgae L.) is grown in Kenya
mainly for malting purposes. The established malting
cultivars are Proctor, Research and Tumaini The
cultivar amani is grown on a limited scale for livestock
feed. Barley research in Kenya is aimed at
improving yield, qual! ty and resistance to diseases.
Genetic studies were undertaken on inheritance
of grain yield and its components such as heads per
plent, grains per head and grain weight, 8S well 8S on
malting quality traits such as grain nitrogen content,
grain moisture content, grain weight and grain germination
percentage. The detailed analysis introduced by
Griffing (1956b) and improved by Gardner and Eberhart
(1956) was used to estimate genetic parsmeterso
Seven parental cultivars, Proctor, Research,
Tumaini, Amani, EBVT/2/77-8, E8VT/9/77-8 and
£BYT/15/77-8, were used in all possible combinations
excluding reciprocals. f~ur of the parental cultivar,
Proctor, Research, Tumaini and Amani~were t~~-row
barley cu1tivars1 and the other three, EBVT/2/77-8,
EBYT/9/77-8 and EBVT/15/77-8, were six-row barley
cultivarso The 21 F,fS and 7 parents were grown in a
randomized complete block design with three replicates
at the National Plant Breeding Station~ Njoro, between
May and October 1979. Five randomly selected plants
II fro~ each plot ~Jere used to get data dn heads per plant,
gl'Bing par h2ad s iDO-grain weight and grain yield per
plnnto The malting quality traits were analysed at the
laboratories of Kenya Breweries Ltd.
The dat.ain the present study indicated that both
additive and non-additive gene effects were responsible
for the manifestation of variability in grain yield per
plant and grains per head though the magnitude of
additive gene variance was greater 1n case of grain yield.
H22ds per plant and grain moisture content were governed
primarily by additive genes. On the other hand 1DO-grain
.w~ight and grain nitrogen content were controlled mainly
by non-additive genese No genetic analysis was required
fer grain g~~nnination percentage as all the samples had
g2~~ination capacity of 99%.
The inheritance of yield traits was found to be
highly infl~2nced by head row pattern. The two-row
c.rl t Lvar s end tllelr crosses had more heads per plant
unrl fewer rr3ins per head than the six-row cultivars
'-lit: the Si),~'I'lH'J x six-row crosses. The two-row par enta
w.'re Let ter general combiners for heads per plant and
~r,';J.n yieJ.c' pur plant than the aix-rou parents. An
exception to this was Amani7 a two-row cultivar, which
was the poorest general combiner for ,grain yield. The
six-row parents had high general combining ability
values for graina per head.
Negative general combining ability values for
grain nitrogen content was obtained for cultivars
established for malting in Kenya. This was desirable
for malting quality requirements since such cultivars
would give hybrid combinations with reduced grain
nitrogen content. Amani and the six-row cultivars,
except EBYT/15/77~8, had positive general combining
ability values for grain nitrogen content. Proctor,
Research and Tumaini had positive general combining
ability values for grain moisture content while Amani
atnhde .six-row parents had low and negative general
combining ability values for this trait. Low parental
combining ability values for grain moisture content
is advantageous in programmes for improving malting
barley because parents with low general combining
ability would give hybrid combinations with reduced
moisture content.
Among the yield components only heads per plant
had a strong positive correlation to ijra1n yield per
plant~ Others had only weak correlations to yield~ The
components had strong negative correlations to each other
(xvii)
except for heads per plant and grain weight which were
not related. There were 9tro~g negative correlations
between grain moisture content and grain weight and
grains per head and grain nitrogen content. On the
other hend grain moisture content B~ci heads per plant,
grain nitrogen content and grain weight were positively | en |
