Molecular Profiling of Major Indian Rice Cultivars Using a Set of Eight Hypervariable Microsatellite Markers

India bred high yielding rice varieties have enriched to a great extent the global rice germplasm since the mid-sixties. Systematic research efforts for development of cultivar-specific DNA fingerprints of major Indian rice cultivars, however, have not received due attention. The present investigation was aimed at development of DNA fingerprints for 90 high yielding rice varieties using hypervariable microsatellite (hvRM) markers. A panel of eight markers, viz. RM11313, RM13584, RM15004, RM5844, RM22250, RM22565, RM24260 and RM8207 was chosen from 52 polymorphic markers based on their highly polymorphic nature, SSR repeat type and number and ability to distinguish genotypes, in order to develop DNA fingerprints of 90 varieties. The remaining high polymorphic hvRM markers could be of immense value in future to distinguish new cultivars, in case they could not be distinguished by the 8 marker panel. Four of the 8 markers, viz. RM22250, RM13584, RM24260 and RM5844 were located in expressed genes and could be of value in DUS (Distinctness, Uniformity and Stability) testing. Thus we suggested, that this set of 8 loci could be used as standard for DNA fingerprinting of Indian rice cultivars

Identification of alternate dwarfing gene sources to widely used Dee-Gee-Woo-Gen allele of sd1 gene by molecular and biochemical assays in rice ( Oryza sativa L.)

After the success of IR8 and TN1, breeders depended heavily on these two rice cultivars for source of short stature led to the narrow genetic base to majority of present day rice varieties, as far as sd1 (semi-dwarf1) gene is concerned. In addition, analysis of genetic lineage of the majority of the cultivated rice varieties in tropical Asia reveals that sd1 from DGWG (Dee-Gee-Woo-Gen) is the source of dwarfing gene. Such high amount of genetic homogeneity renders rice plants vulnerable to epidemic of diseases and insect pests. In the current study, we made an attempt to identify the alternate sources of DGWG allele of sd1 gene by characterizing 29 induced and 3 spontaneous dwarf accessions employing marker for DGWG allele of sd1 gene and exogenous application of gibberellic acid (GA3). When occurrence of DGWG allele of sd1 gene and GA3 response were analyzed together, existence of two kinds of dwarfs was noticed viz., dwarf accessions with DGWG allele and dwarf accessions without DGWG allele of sd1 allele exhibiting varying responses to GA3. As many as 22 of 32 dwarf accessions showed absence of DGWG allele of sd1 gene with varying response to GA3 could be used as excellent alternate sources for DGWG allele of sd1 gene. These dwarf accessions could be used for broadening the genetic base for the plant height and thereby minimize the risk of genetic vulnerability. Our strategy of combining molecular and biochemical assays can be efficiently used for identifying alternate dwarfing gene sources to the Green Revolution gene sd1

Identification of alternate dwarfing gene sources to widely used Dee-Gee-Woo-Gen allele of sd1 gene by molecular and biochemical assays in rice ( Oryza sativa L.)

After the success of IR8 and TN1, breeders depended heavily on these two rice cultivars for source of short stature led to the narrow genetic base to majority of present day rice varieties, as far as sd1 (semi-dwarf1) gene is concerned. In addition, analysis of genetic lineage of the majority of the cultivated rice varieties in tropical Asia reveals that sd1 from DGWG (Dee-Gee-Woo-Gen) is the source of dwarfing gene. Such high amount of genetic homogeneity renders rice plants vulnerable to epidemic of diseases and insect pests. In the current study, we made an attempt to identify the alternate sources of DGWG allele of sd1 gene by characterizing 29 induced and 3 spontaneous dwarf accessions employing marker for DGWG allele of sd1 gene and exogenous application of gibberellic acid (GA3). When occurrence of DGWG allele of sd1 gene and GA3 response were analyzed together, existence of two kinds of dwarfs was noticed viz., dwarf accessions with DGWG allele and dwarf accessions without DGWG allele of sd1 allele exhibiting varying responses to GA3. As many as 22 of 32 dwarf accessions showed absence of DGWG allele of sd1 gene with varying response to GA3 could be used as excellent alternate sources for DGWG allele of sd1 gene. These dwarf accessions could be used for broadening the genetic base for the plant height and thereby minimize the risk of genetic vulnerability. Our strategy of combining molecular and biochemical assays can be efficiently used for identifying alternate dwarfing gene sources to the Green Revolution gene sd1

MICROSATELLITE ANALYSIS OF INTRA CULTIVAR DIVERSITY IN \u2018CHINNARASAM\u2019 MANGO FROM ANDHRA PRADESH, INDIA

\u2018Chinnarasam\u2019, a juicy cultivar of mango ( Mangifera indica L.), is among the most important mangoes of an Indian State of Andhra Pradesh, whose production and quality is variable across the State. Twenty accessions of \u2018Chinnarasam\u2019 (CR Acc-l to CR Acc-20) were selected from 9 locations spread over 6 districts, representing all the three eco-geographical regions (Coastal Andhra, Rayalaseema and Telangana) of Andhra Pradesh. Their leaves were sampled to study intracultivar diversity following microsatellite analysis. The dendrogram generated based on unweighted pair group mean with arithmetic average, showed three major groups of accessions, which followed geographical separation. Twenty out of 109 mango-specific microsatellites validated, were polymorphic (18.34%). Microsatellites produced a total of 62 alleles, of which 31 were polymorphic (50%). The Jaccard\u2019s similarity coefficient ranged from 0.54 to 1.00. Existence of intracultivar genetic diversity (up to 46%) indicates that \u2018Chinnarasam\u2019 whatsoever cultivated throughout the State is not a pure clone, which allows the genetic breeding of this cultivar by means of mass selection. Microsatellite markers have proven useful in assessing intracultivar genetic diversity and identifying accessions of \u2018Chinnarasam\u2019 cultivar.\u2018Chinnarasam\u2019, un cultivar juteux du manguier ( Mangifera indica L.), est parmi les manguiers d\u2019un Etat indien d\u2019Andhra Pradesh, dont la production et la qualit\ue9 sont variables \ue0 travers la r\ue9gion. Vingt nouvelles accessions de \u2018Chinnarasam\u2019 (CR Acc-l \ue0 CR Acc-20) \ue9taient s\ue9lectionn\ue9es parmi 9 lieux de propagation sur 6 districts repr\ue9sentant toutes les trois r\ue9gions eco-g\ue9ographiques d\u2019Andhra Pradesh (la partie coti\ue8re d\u2019 Andhra, Rayalaseema et Telangana). Leurs feuilles \ue9taient \ue9chantillonn\ue9es pour \ue9tudier la diversit\ue9 intracultivar suivant l\u2019analyse microsatellite. Le dendrogramme g\ue9n\ue9r\ue9 sur base de la moyenne du groupe paire non pond\ue9r\ue9e avec la moyenne arithm\ue9tique a montr\ue9 trois groupes importants d\u2019 accessions en rapport avec la s\ue9paration g\ue9ographique. Vingt sur 109 microsatellites sp\ue9cifiques de manguiers valid\ue9s \ue9taient polymorphes (18.34 %). Les microsatellites ont produit un total de 62 all\ue8les parmi lesquelles 31 \ue9taient polymorphes (50 %). Le coefficient de similarit\ue9 de Jaccard variait de 0.54 \ue0 1.00. L\u2019existence de diversit\ue9 g\ue9n\ue9tique intracultivar (jusqu\u2019\ue0 46 %) indique que le \u2018Chinnarasam\u2019 cultiv\ue9 \ue0 travers l\u2019 Etat n\u2019est pas un clone pur, ce qui permet l\u2019am\ue9lioration g\ue9n\ue9tique de ce cultivar par le moyen de la s\ue9lection massive. Les marqueurs microsatellites se sont av\ue9r\ue9s utiles dans l\u2019\ue9valuation de la diversit\ue9 g\ue9n\ue9tique intracultivar et l\u2019identification des accessions du cultivar \u2018Chinnarasam\u2019

MICROSATELLITE ANALYSIS OF INTRA CULTIVAR DIVERSITY IN ‘CHINNARASAM’ MANGO FROM ANDHRA PRADESH, INDIA

‘Chinnarasam’, a juicy cultivar of mango ( Mangifera indica L.), is among the most important mangoes of an Indian State of Andhra Pradesh, whose production and quality is variable across the State. Twenty accessions of ‘Chinnarasam’ (CR Acc-l to CR Acc-20) were selected from 9 locations spread over 6 districts, representing all the three eco-geographical regions (Coastal Andhra, Rayalaseema and Telangana) of Andhra Pradesh. Their leaves were sampled to study intracultivar diversity following microsatellite analysis. The dendrogram generated based on unweighted pair group mean with arithmetic average, showed three major groups of accessions, which followed geographical separation. Twenty out of 109 mango-specific microsatellites validated, were polymorphic (18.34%). Microsatellites produced a total of 62 alleles, of which 31 were polymorphic (50%). The Jaccard’s similarity coefficient ranged from 0.54 to 1.00. Existence of intracultivar genetic diversity (up to 46%) indicates that ‘Chinnarasam’ whatsoever cultivated throughout the State is not a pure clone, which allows the genetic breeding of this cultivar by means of mass selection. Microsatellite markers have proven useful in assessing intracultivar genetic diversity and identifying accessions of ‘Chinnarasam’ cultivar.‘Chinnarasam’, un cultivar juteux du manguier ( Mangifera indica L.), est parmi les manguiers d’un Etat indien d’Andhra Pradesh, dont la production et la qualité sont variables à travers la région. Vingt nouvelles accessions de ‘Chinnarasam’ (CR Acc-l à CR Acc-20) étaient sélectionnées parmi 9 lieux de propagation sur 6 districts représentant toutes les trois régions eco-géographiques d’Andhra Pradesh (la partie cotière d’ Andhra, Rayalaseema et Telangana). Leurs feuilles étaient échantillonnées pour étudier la diversité intracultivar suivant l’analyse microsatellite. Le dendrogramme généré sur base de la moyenne du groupe paire non pondérée avec la moyenne arithmétique a montré trois groupes importants d’ accessions en rapport avec la séparation géographique. Vingt sur 109 microsatellites spécifiques de manguiers validés étaient polymorphes (18.34 %). Les microsatellites ont produit un total de 62 allèles parmi lesquelles 31 étaient polymorphes (50 %). Le coefficient de similarité de Jaccard variait de 0.54 à 1.00. L’existence de diversité génétique intracultivar (jusqu’à 46 %) indique que le ‘Chinnarasam’ cultivé à travers l’ Etat n’est pas un clone pur, ce qui permet l’amélioration génétique de ce cultivar par le moyen de la sélection massive. Les marqueurs microsatellites se sont avérés utiles dans l’évaluation de la diversité génétique intracultivar et l’identification des accessions du cultivar ‘Chinnarasam’

Caracterização e avaliação de três grupos de arroz-de-sequeiro de diferentes procedências por meio da sensitividade à radiação gama Characterization and evaluation of three groups of rice upland of different origins through gamma-ray sensitivity

A caracterização e avaliação de variedades de arroz auxiliam na seleção dos parentais e na ampliação da base genética dos programas de melhoramento. Este trabalho teve como objetivo caracterizar e avaliar três grupos de arroz-de-sequeiro (Oryza sativa L.) de diferentes procedências por meio da sensitividade à radiação gama. Sementes de 84 variedades procedentes do Japão, Filipinas e Brasil foram submetidas a v��rias dosagens de radiação gama e semeadas em caixas de madeira no delineamento em blocos completos ao acaso com três repetições. O experimento foi instalado em casa de vegetação, em 1991, no Centro de Energia Nuclear na Agricultura (CENA), da Universidade de São Paulo (USP). Mediu-se a sensitividade por meio dos efeitos fisiológicos produzidos na geração M1; determinaram-se as porcentagens de emergência, a sobrevivência e a altura das plântulas. Os resultados mostraram diferenças significativas de sensitividade à radiação gama entre grupos em todos os caracteres avaliados.<br>The characterization and evaluation of varieties of rice aid in the parents selection and in the increase of the genetic base of breeding programs. The present work was carried out to characterize and to evaluate three groups of rice upland (Oryza sativa L.) of different origins through gamma-ray sensitivity. Seeds of 84 varieties collected from Japan, Philippines and Brazil, were submitted to various doses of gamma-radiation and sown in wooden boxes. The experiment was conducted in 1991 at greenhouse according to randomized complete block design with three replications. Physiological effects caused by radiation in the M1 generation, such as seed emergency, seedling height and survival rate, were determined and evaluated. The results showed significant differences of sensitivity to the radiation among three groups for all traits evaluated