PhD

An experiment on "Genetic analysis of yield and quality attributes in
fodder cowpea [Vigna unguiculata (L.) Walp.]" was carried out at the
Department of Plant Breeding anti Genetics, College of Agriculture,
Vellayani during 1999-2002 with the objective of estimating combining
ability heterosis and gene action.
Fifty one diverse genotypes were evaluated for yield and quality
attributes. Each genotype was replicated twice. The observations on plant
height, number of primary branches per plant, number of leaves per plant, total
, .
leaf area, days to 50 per. cent flowering, days to maturity, leaf/stem ratio, leaf
area index, dry weight of leaf, dry weight of stem, green fodder yield, dry
matter yield, crude protein content, crude fibre content, calcium content and
phosphorus content were recorded. Variability studies indicated high GCV and
pev for dry weight of stem, dry matter yield and green fodder yield. High
estimates of heritability (>70 per cent) were recorded for all the characters
except number of primary branches per plant. High heritability and
genetic advance were observed for dry weight of stem, dry weight of leaf,
green fodder yield, dry matter yield, leaf area index and crude fibre
content.
Leaf/stem ratio, leaf area index, dry weight of stem, dry weight of leaf,
plant height and number of primary branches per plant showed positive
significant correlation with both green fodder yield and dry matter yield. A
discriminant function was fitted with 12 variables to derive a selection index for
51 accessions based on their yield and yield attributes. The top ranking seven
accessions, IFC 95102, IFC 8401, UP 9001, EC 4216, EC 240744, EC 241027
and HES 82 were selected as lines (female parents) for hybridization. Another
discriminant function was fitted to derive a selection index to evaluate the
quality parameters viz., crude protein content and crude fibre content. Three top





ranking accessions not selected as lines were selected as testers (EC 241044,
N 311 and UPC 953).
Combining ability analysis showed that the lines IFC 8401 and IFC
95102 were good general combiners for green fodder yield and the line IFC
8401 was a good general combiner for dry matter yield. Among the twenty
one hybrid combinations, significant sea variance was observed in the hybrids
IFC 95102 x EC 241044, RES 82 x EC 241044, EC 2416 x UPC 953 and EC
241027 x UPC 953 for green fodder yield and dry matter yield. The hybrid
RES 82 x EC 241044 exhibited high sea significance for plant height, number
of leaves per plant, total leaf area, leaf area index, dry weight of leaf, dry
weight of stem, crude protein content, calcium content and phosphorus content
and significant negative significance for days to maturity. The hybrid EC
241027 x UPC 953 also exhibited superior values for most of the characters.
Of the twenty one hybrids, five combinations viz. IFC 95102 x EC
241044, RES 82 x EC 241044, IFC 8401 x EC 241044, EC 241027 x UPC
953 and IFC 95102 x N 311 excel others by exhibiting positively
significant heterosis for most of the characters including green fodder
yield and dry matter yield.
These five hybrids were used for studying in vitro dry matter
digestibility and the percentage IVDMD was between 56 and 70.
In the F 2 population the mean and variance were estimated and here
also the hybrid HES 82 x EC 241044' gave superior mean values for all
characters studied .
. The hybrids RES 82 x EC 241044 and EC 241027 x UPC 953 were
identified as the promising hybrids and they can be carried forward to
develop fodder varieties with high yield and quality.