Guava world-wide breeding: major techniques and cultivars and future challenges
2012
Pommer, C.V.
Guava is one of the most important fruits in a large number of countries of the world. In most countries where guava is important, genetic studies and breeding is done in different degrees and ways. Germplasm conservation and studies are practiced in places such as Colombia, Venezuela, USA, Malaysia and Nigeria. In these and other cases, objectives are to collect, introduce, characterize and select guava genotypes with defined and appropriate characteristics to production. Artificial pollination is mostly used. Conversely, countries such as Israel, Thailand, Cuba, Mexico, Brazil, Pakistan and India, especially the latter one, present active and productive guava breeding programs. On the other hand, this fact resulted in a very high variability in seedling populations from which promising genotypes have been selected, such as 'Paluma', the main Brazilian cultivar and many others, like 'Kumagai', 'Pedro Sato', 'Cortibel'. In India there are more than 150 cultivars, but only a few with commercial importance such as 'Allahabad Safeda', 'L-49' ('Sardar'), 'Hisar Surkha', 'Lucknow Safeda', 'Arka Amulya', which have been identified for commercial planting particularly in northern India, the main guava growing region. However, in the last 10-15 years crop improvement work carried out resulted in release of several superior selections and or hybrids, such as 'Safed Jam', 'Kohir Safeda' and 'Arka Amulya' in India, 'Século XXI' in Brazil, and others. Breeding programs also use techniques such as interspecific crosses and induced mutation, contributing to bring variability in different senses and characteristics. Molecular techniques and other new biotechnological tools are very helpful to study the extent of genetic variation among cultivars as well as to find out genetic markers for wilt resistance to improve efficiency in developing wilt resistant clones and rootstocks. Development studies still have to be done in aneuploidy breeding, development of autotetraploids and in vitro genetic manipulation of somatic cells.
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