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RA 00110.pdf - OAR@ICRISAT

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Diseases. Diseases are endemic to pearl millet in<br />

India. Depending on weather conditions and genotype,<br />

downy mildew, ergot, and smut assume epidemic<br />

proportions. Downy mildew is a recurring<br />

threat, threatening high-yielding varieties since the<br />

1970s. Ergot and smut lower only grain yield, but<br />

downy mildew also kills plants.<br />

Research Strategies<br />

Genetic Resources<br />

The pearl millet germplasm collection at I C R I S A T<br />

is 17 621 accessions from 42 countries as of September<br />

1985. To be more useful, the morphological, physiological,<br />

and biochemical characteristics of the accessions<br />

should be published in a catalogue, which<br />

would stimulate use of the collection.<br />

Breeding Hybrids and Varieties<br />

Heterogeneous hybrids. Phenotypically and genotypically<br />

homogeneous pearl millet hybrids are produced<br />

by crossing two inbred lines. This uniformity<br />

makes the hybrids vulnerable to diseases and pests.<br />

There is evidence that open-pollinated varieties are<br />

less susceptible to ergot and smut since they flower<br />

less synchronously, and pollination protects against<br />

these diseases. The use of partially inbred or openpollinated<br />

restorers introduces phenotypic and genotypic<br />

heterogeneity into the hybrids, and may reduce<br />

disease incidence.<br />

Multicross hybrids. The single-cross pearl millet<br />

hybrids are quickly becoming vulnerable to diseases,<br />

particularly downy mildew, because of genetic homogeneity.<br />

Triple- and double-cross hybrids may provide<br />

phenotypic and genetic heterogeneity to resist<br />

diseases.<br />

Bold-seeded hybrids and varieties. Seed size is a<br />

significant component of grain yield. The commercial<br />

hybrids and varieties have small- to mediumbold<br />

grains, 4-6 g per 1000 grains, but grain size can<br />

vary from 2-14 g per 1000 grains. The private sector<br />

hybrids M B H 110 and M B H 118 are also bold<br />

seeded. It has become necessary to combine bold<br />

seed with higher effective tillering in male-sterile<br />

lines, restorers, and parents of open-pollinated varieties<br />

to produce higher-yielding, bold-grained hybrids<br />

and varieties.<br />

Sweet pearl millets. The need for dual-purpose<br />

grain and fodder pearl millet hybrids and varieties<br />

requires the attention of research workers. Brix<br />

readings can vary from 3-16%. The value of pearl<br />

millet would rise substantially if sweet pearl millets<br />

for sugar extraction could be bred.<br />

White- and yellow-grained pearl millets. Whitegrained<br />

pearl millets have an attractive color, high<br />

protein content, and are sweet. Yellow-grained pearl<br />

millets are rich in carotene, the precursor of vitamin<br />

A. The development of nutritionally superior whiteand<br />

yellow-grained pearl millets would enhance the<br />

food value of the millet consumed by the poorest<br />

section of the population, and may find a place in<br />

irrigated farming.<br />

Manipulation of Production<br />

Processes<br />

Adaptation, tillering, and plant density. High tillering<br />

potential appears to confer adaptive advantage<br />

to pearl millet in the semi-arid tropics. Low<br />

plant densities appear to promote tillering. Hybrids<br />

which have high tillering yielded more grain at low<br />

plant densities than composites and landraccs (Harinarayana<br />

1980).<br />

Tillers are produced at the base and nodal points.<br />

The ratio of effective to basal tillers (0.35) favors<br />

basal tillers in hybrids compared to varieties (0.59)<br />

indicating that all basal tillers are not productive<br />

(Harinarayana 1980), and hence the source of photosynthates<br />

is limiting. Tillering differences indicate<br />

the necessity to intensify studies on tillering potential<br />

of different millet genotypes in relation to plant<br />

densities.<br />

Dry matter production and distribution. Hybrids<br />

and improved varieties produced more dry matter<br />

than local varieties. In spite of comparable harvest<br />

indices, hybrids produced higher grain yield than<br />

varieties, indicating high dry matter production and<br />

efficient distribution. Differences were also observed<br />

between early and late hybrids, and hybrids with<br />

common female and male parents. A l l these indicate<br />

the immense potential for breeding hybrids and varieties<br />

with higher harvest indices, or increased<br />

fodder production ( A I C M I P 1980).<br />

Effective water use. Nearly 40% of the cultivated<br />

area in India is likely to be irrigated during the 1980s.<br />

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