10
PNL Volume 18 1986 RESEARCH REPORTS
EFFECT OF YEAR AND SPACING ON COMBINING ABILITY IN PEA
Csizmadia, L.
Research Station of Vegetable Crops Research Institute
Ujmajor, Hungary
Estimates of general and specific combining ability effects and
variances are generally obtained from space planted experiments and in most
cases are not repeated over years or locations. Little is known of the
extent of different genotype x environment interactions and Co what extent
they affect the general (GCA) and specific combining ability (SCA)
variances. The present investigation was undertaken to provide information
on these aspects.
Ten pea varieties and lines (RS-455, Br-52, 'Jof', 'Puget'
'Multipod', 'Extra Rapide ' , Wav. 01, 'Skinado', Wav. 180045, FJ-111) were
crossed in all possible combinations, excluding reciprocals. Parents and
F1 progenies were evaluated in two years in space planted experiments
(single row plots, rows spaced 1 m apart, 20 cm plant-to-plant spacing),
parents, and F2 progenies in one year in a wide (as in F1 ) and in a narrow
spaced experiment (4-row plots, rows spaced 15 cm apart with 10 cm plant-
to-plant spacing). Each experiment was arranged in a randomized block
design with three replications. Plot means were subjected to analysis of
variance and significant interaction variances were analyzed following
Griffing's method II (both fixed and random effects models were studied) as
detailed by Singh (1).
Analysis of variance for combining ability showed that the mean
squares due to GCA, SCA, year effect (in F1), and spacing effect (in F2)
were highly significant for all traits. GCA x year and GCA x spacing
components of interaction variances were significant for all characters
except for seeds per 5 pods. SCA x year was significant only for pods per
plant and SCA x spacing only for seeds per 5 pods (Table 1).
Estimates of various genetic parameters and heritabi1ities are shown
in Table 2. In accordance with the data of Table 1, estimates of s2g and Hn
were higher for seeds per 5 pods and 100 seed weight both in F1 and F2.
Due to space limitations, estimates of various effects are not
presented here, only correlations between GCA; means of parents and CCA x L
are recorded in Table 3. There are significant correlations between GCA
vs. means of parents (both in F1 and F2) GCA in F1 vs. GCA in F2 for each
character. In spite of the significant interactions estimates of general
combining ability seem unbiased.
1. Singh, D. 1973. Indian J. Genet. 33:469-481
PNL Volume 18 1986 RESEARCH REPORTS
12
PNL Volume 18
1986
RESEARCH REPORTS
 
 
   
 
 
 
       
Hosted by uCoz