Mutagenesis—A Potential Approach for Crop Improvement - Crop Improvement: New Approaches and Modern Techniques - page 150

Lesions IN Genomes), high-resolution melt analysis (HRM), ECOTILLING etc.
are the key techniques and resources in molecular mutation breeding. Molecular
mutation breeding will significantly increase both the efficiency and efficacy of
mutation techniques in crop breeding. Such modern and classical technologies are
using for the development of mutation induction with the objective of using a set
of globally important crops to validate identified relevant novel techniques and
build these into modular pipelines to serve as technology packages for induced
crop mutations. Thus, mutation assisted plant breeding will play a crucial role in the
generation of 'designer crop varieties' to address the uncertainties of global climate
variability and change, and the challenges of global plant-product insecurity.
Introduction
Mutation breeding is the purposeful application of mutations in plant breeding area.
It offers good prospects for the domestication of promising underutilized wild spe-
cies, for agricultural or horticultural uses as well as for improving adaptation of
recently introduced crops to unsuitable environments. Mutagenesis has remained
popular for close to a century because of its simplicity, technical and economic via-
bility, applicability to all plant species and usability at small or large scales (Siddiqui
and Khan 1999 ). More than 2,000 plant varieties that contain induced mutations
have been officially released for cultivation either directly as new varieties or used
as parents to derive new varieties without the regulatory restrictions faced by ge-
netically modified material (Maluszynski et al. 2000 ; Waugh et al. 2006 ). The main
strategy in mutation-based breeding has been to upgrade the well-adapted plant
varieties by improving a few desirable major yield and quality traits (Ahloowalia
et al. 2004 ; Wilde et al. 2012 ). Besides, the increased yield and enhanced quality of
the novel varieties included several other components such as subsequent use for
breeding, improved harvest index from heterosis in hybrid cultivars, response to
increased agronomic inputs, and consumer preference.
Plant breeding categorized into three sub-types as mutation breeding, recombi-
nation breeding and transgenic breeding has the potential of generating variation
and selection of target lines. In case of mutation breeding, the basic fundamental
and the unique feature is the generation of new mutated alleles. The key steps
includes analysis of difference in the sensitivity of different genotypes and plant
tissues to different mutations often measured using lethal doses (LD), generation
of genetic chimeras after mutagenic treatment and analysis of their effect on trans-
mission of mutated alleles and segregation in the subsequent generation and also
often the recessive nature of induced mutations. This knowledge is important for
establishing proper doses and modes of mutagenic treatment. Apart from this, the
knowledge can also be employed for the planning of methodology of harvesting
and growing second mutant (M 2 ) populations from first mutant (M 1 ) generations
(Table 4.1 ). Like any other scientific innovative technology, mutation breeding has
its advantages and limitations. The advantages being creation of new genetic al-