Characterization of advanced inbred lines for low phosphorus and iron toxicity tolerance
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Date
2018
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College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University, Imphal
Abstract
Rice (Oryza sativa) is the world’s most important food crop and it’s productivity is adversely affected by many biotic and abiotic factors. Nutrient deficiency and mineral toxicities are one of the major problems affecting rice productivity, these problems are mainly associated with soil pH especially acidity/sodicity. In India, major portion of soil affected by acidity are concentrated in north-eastern part of India. Phosphorus (P) deficiency and severe iron toxicity in acid soil leads to poor growth and yield reduction in rice. Therefore, it is necessary to develop the rice genotypes with tolerance to iron toxicity and phosphorus deficiency performing well in lowland acidic soil conditions.Towards this end, an attempt was made to evaluate two advanced breeding lines for iron toxicity and low P tolerance in lowland acidic field with the following objectives: 1) to characterize the set of advanced inbred lines with respect to yield contributing traits and 2) to genotype advance inbred lines by using DNA based markers. Out of 51(BC2F9) near isogenic lines (NIL) and recombinant inbred lines (RIL) (235 plants) (F3:4) grown in the lowland acidic field conditions, a set of top performing KM lines and ULRC-36 plants were selected based on the phenotypic data such as bronzing score at 45 and 60 days after transplanting (DAT), tiller number (TN) at 60 DAT, panicle number (PN), test weight (TW), spikelet fertility (SF). The selected lines showed variation for the traits under study. The highest test weight was observed in KM-194and ULRC-36-8 followed by ULRC-55 in NILs and RILs mapping population, respectively. In NILs population KM-194 performed well for P content, phosphorous uptake (PUP) and showed no bronzing. KM-608 performed better for phosphorous use efficiency (PUE).The highest tiller number at 60 DAT was recorded in KM-660. In case of ULRC-36, the highest P content, PUP and PUE was observed in ULRC-36-152, ULRC-36-242 and ULRC-105, respectively. Among the selected plants, no bronzing was found in ULRC-36-22, ULRC-36-157, ULRC-36-175 and ULRC-36-253. For tiller number at 60 DAT, plants ULRC-36-22, ULRC-36-107, ULRC-36-152, ULRC-36-157 and ULRC-36-278 showed performance better than the parents. Correlation study for the traits under study showed positive correlation at 1% and 5% level of significance for the key trait likes TN, PN, grain yield and other traits in the both populations. Six trait specific molecular markers for low P tolerance and Fe toxicity also showed variation for the selected genotypes and the desired alleles were present in some of the top performing lines.The selected KM lines can be tested for seed quality traits andthe ULRC-36 population further advanced before genetically fixed lines can be selected.