Training Manual Development Of Cultivars And Seed ... - icrisat

Certification requirements:
Stable male sterility of seed parent, unique trait combinations.
Factors to be considered when choosing breeding objectives are the importance of the trait,
availability of genetic variability for the trait (preferably in desirable agronomic backgrounds), availability
of cost-efficient screening procedures for the trait, and the time available before another cultivar release
is needed.
Once these general breeding objectives are identified, it is necessary to decide upon the form of
the genetic package to be delivered to farmers. Only after this decision is made is it really possible to
develop reasonable work plans to do the breeding research required to deliver an adoptable cultivar to
farmers.
Cultivar Types
Pearl millet cultivars are of two types: open-pollinated cultivars and hybrid cultivars. Open-pollinated
cultivars differ from hybrids primarily in their ability to self-perpetuate and the degree of variability
available in them. Seed harvested from an isolated plot of an open-pollinated cultivar will have essentially
the same yield potential and uniformity as the crop from which it was harvested. However, in case of
hybrids it is necessary to reconstitute the cultivar by crossing its parents to produce fresh seed to retain
uniformity and yield potential of the hybrid cultivar.
Hybrid cultivars have several advantages to seedsmen and farmers compared to open-pollinated
cultivars. They include higher yield potential within a given maturity, ability to combine desirable
characters from different parents into a single cultivar, and greater uniformity (facilitating birdscaring and
harvest operations). Further, closed pedigrees and the necessity of reconstituting hybrids from their
parents allow private industry to protect their intellectual property resulting from their investment in
research and development.
The advantages of open-pollinated varieties are of two types: (1) their ability to self-replicate
(facilitating farmer-to-farmer spread), and (2) their inherent genetic variability. This variability within openpollinated
varieties contributes to stability of performance by reducing risks of crop failure due to drought,
downy mildew, ergot, and smut.
Open-Pollinated Cultivars
There are three general types of open-pollinated cultivars of pearl millet:
1. Mass-selected landraces
2. Products of recurrent selection within a breeding population
(a) Cycle bulk
(b) Recombination of selected progenies
3. Synthetic varieties bred by random mating a set of inbred lines
Broadly, open-pollinated varieties are products of traditional crop improvement by farmers, or bred
by random mating a selected fraction of a variable breeding population.
Hybrid Cultivars
Several types of hybrid cultivars are possible, depending on the genetic structure of their parental lines.
35