MARKER BASED HETEROTIC POOLING OF DIVERSE ASIAN AND AFRICAN PEARL MILLET [Pennisetum glaucum (L.) R. Br.] POPULATIONS
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Date
2019
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PROFESSOR JAYASHANKAR TELANGANA STATE AGRICULTURAL UNIVERSITY
Abstract
A set of 45 diverse Asian and African populations of pearl millet were
investigated for molecular and morphological genetic diversity. Multivariate analysis
based on multi-location evaluation for grain yield and its component traits grouped these
populations into five clusters. Most populations of Asian origin grouped into common
cluster and separated from rest of the populations of African origin indicating the
presence of correspondence between clustering pattern and geographical origin.
Molecular diversity assessed using 29 SSRs detected 435 alleles (average of 15 alleles
per locus) and grouped 45 pearl millet populations into seven different clusters.
Clustering pattern, population structure analysis and principal coordinate analysis
revealed intermixing of African and Asian origin populations, whereas most of all the
African origin and Asian bred populations were found grouped into common clusters.
The correlation between genetic distance estimated through morphological traits and
through SSRs was non-significant (r = -0.13).
Fourteen parental populations representing seven marker based clusters were
used to develop 91 population hybrids (in diallel fashion). These population hybrids
were evaluated at three locations for grain yield and its component traits. The
correlation between genetic distance (GD) between parental lines and heterosis for grain
yield was negative and significant (r = -0.37, p < 0.001) indicating that prediction of
hybrid performance based on GD may not be feasible. However, lesser negative
correlation was found at lower GD (0.60-0.68) than in comparison of hybrids developed
using parental populations with higher GD (0.78-0.86). Based on hybrids performance,
heterosis and combining ability among marker group based crosses, two heterotic pools
(PMPHP-1 and PMPHP-2) were identified having significant levels of heterosis (PMpH
= 20% and PBpH = 6.8%). Populations of PMPHP-1 had linkages with African origin
and Asian origin populations, whereas PMPHP-2 composed of exclusively African
origin and Asian bred populations. Following the second approach of heterotic pool
formation which is based on grain yield based combining ability patterns, 14 parental
populations were grouped into three heterotic pools (PMPHP-A, PMPHP-B and
PMPHP-C).
Fertility restoration/maintainer frequency of 45 populations on three diverse
CMS systems (A1, A4 and A5 cytoplasm) evaluated in two contrasting seasons (summer
and rainy) revealed that fertility restoration frequency (%) was highest for A1 CMS
(86%) followed by A4 CMS (37%) and least for A5 CMS (7%). Based on fertility
restoration/maintainer frequency, heterotic pool PMPHP-1 populations with high grain
yield and bold seeds were proposed to be utilized in maintainer lines (B-lines) and
PMPHP-2 having populations with high fertility restoration ability were identified for
restorer lines (R-lines) development programs, which can further be utilized to diversify
the existing maintainers and restorer parents of different CMS systems.
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D10,409