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Subject: Plant Breeding × Author: Rahul Kumar × End date: 2012 × Start date: 2012 ×
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    ThesisItemOpen Access
    EVALUATION OF CULTIVATED AND WILD ORYZA SPECIES FOR IRON UPTAKE UNDER AEROBIC CONDITIONS AND VARIATION IN IRON TRANSPORTER GENES
    (Punjab Agricultural University, Ludhiana, 2012) Rahul Kumar
    The cultivation of transplanted rice in northwest plains of India has lead to depletion of ground water to almost alarming level. Replacement of rice with other water requiring crop or changed production technology that will require less water has become essential. Cultivation of direct seeded rice under aerobic conditions is an alternative production technology that is expected to use less water, but it will require an altogether a different ideotype, one of the stresses the aerobic rice face is iron deficiency induced chlorosis. The present study focused on evaluation of cultivated and wild Oryza species for iron uptake under aerobic conditions and variation in iron transporter gene. Three hundred twenty Oryza accessions including six Oryza glaberrima, 105 O. rufipogon, 193 O. nivara, one barthii and 15 cultivated Oryza sativa genotypes were evaluated for iron deficiency induced chlorosis (IDC), days to 50% flowering; leaf area index and SPAD value. Some genotypes were tolerant to IDC throughout the growth period while other showed varying degree of chlorosis at the different stages. Based on the IDC score, 59 accessions including 49 tolerant and 10 susceptible were short listed for molecular studies and further evaluation. Basmati 370, Basmati 386, Lemont, PAU 201in cultivated varieties and O. nivara (CR 100003) and O. rufipogon (CR 100343) in wild species performed best under aerobic conditions with minimum or no chlorosis and desirable SPAD reading and LAI. These could be useful in aerobic rice breeding programme. In a hydroponics experiment O. rufipogon acc. CR 100001, O. nivara acc. CR 100127 and Basmati 370 showed better tolerance to IDC along with good SPAD value and high iron content in leaves. Microsatellite markers developed from 23 iron homoeostasis gene sequence were used for characterizing the 59 selected genotypes. Based on the variation in the 23 Fe homoeostasis genic SSRs markers, the 59 genotypes were clustered into three groups, significance of which is discussed.