21 research outputs found
Inheritance pattern and gene action of brown planthopper (Nilaparvata lugens Stäl.) resistance in newly identified donors of rice (Oryza sativa L.)
Brown planthopper (BPH) is one of the destructive insect pests causing significant yield losses in rice. BPH causes direct damage to the rice plants by sucking the sap from phloem, causing hopper burn and transmitting viral diseases like grassy and ragged stunt viruses. Several resistant donors have been identified from time to time, but the new biotypes of the pest arise to defeat the extended use of resistance genes in a single variety. This necessitates the regular identification of new resistant donors along with their nature of inheritance and gene action controlling the resistance. Knowing the inheritance pattern, gene action and number of genes controlling a trait helps the plant breeders to plan the effective breeding approaches for crop improvement. The present investigation was hence carried out to know the inheritance pattern, gene action and number of genes controlling BPH resistance in newly identified sources. The results indicated that the BPH resistance in PHS 29 genotype is under the control of single recessive gene. Whereas, it is controlled by two recessive genes in MRST 3 genotype. This reveals that relatively higher population size will be required to recover desirable segregants in the segregating populations involving MRST 3 genotype as one of the parents as compared to that involving PHS 29 genotype as parent. Since, the resistance in both the cases being recessive in nature, the trait will hence show significant additive effect, indicating that pure line development will be desirable for improvement of such a trait
Pollen preservation potential of Imperata cylindrica — an efficient source for doubled haploid production in wheat
Pollen of two I. cylindrica genotypes, one having spike with brown anthers (Ic-Pbr) and other with yellow anthers (Ic-Pye) was collected from three collection environments (early, mid and late flowering) and preserved in sealed Petri dishes under three preservation regimes, P1 (4 °C temperature and 60% RH), P2 (–20 °C and 65% RH) and P3 (–80 °C temperature and 45% RH). The pollen viability and germination tests of the preserved pollen were conducted after every 15 days till complete loss of viability. The study revealed that Ic-Pbr was superior to Ic-Pye in terms of the mean absolute pollen viability (APV) under preservation conditions. Among the collection environments, pollen collected just after first anthesis, that is, early flowering was superior in terms of the preservation potential. The preservation regime, P2 was found to be best among the three for better preservation of I. cylindrica pollen. By utilizing the one month old preserved pollen for pollination of wheat spikes, pollen from P2 regime induced haploid embryos to the tune of 25.53%. The study concluded that by preserving I. cylindrica pollen at –20 °C, the period of DH production in wheat can be extended by at least one month. The preserved pollen will also open avenues for exploring the possibilities of inducing haploids in other cereals like rice and maize whose flowering does not coincide with I. cylindrica naturally
Proportional Contribution and Potential of Maternal and Paternal Genotypes for Polyhaploid Induction in Wheat Ă— Imperata cylindrica Chromosome Elimination Approach
The Imperata cylindrica-mediated chromosome elimination approach has been identified as the most efficient system of doubled haploidy breeding in wheat (Triticum aestivum L.). The present investigation was carried out to assess the mean performance of diverse I. cylindrica genotypes (five) collected from different locations and wheat F1s (21) generated out of various elite winter and spring wheat ecotypes. Also, the proportional contribution of wheat F1s and I. cylindrica genotypes was evaluated to find out the relative contribution of maternal and paternal parents to haploid induction. The investigation revealed that the mean response of wheat and I. cylindrica to haploid induction parameters, viz. pseudoseed formation, embryo formation, haploid regeneration and haploid formation varies from wheat and I. cylindrica genotype to genotype. The I. cylindrica genotype, Ic-Aru from north east Himalayas and wheat genotype, DH 114 Ă— KWS 29 exhibited highest mean performance to haploid embryo formation, the stage for which all the three contributors, that is, wheat F1s, I. cylindrica genotypes and wheat Ă— I. cylindrica interaction were found to be similar for their proportional contribution (%) towards haploid induction. Thus, concluding that the haploid induction through preferential chromosome elimination approaches can be enhanced by using more efficient pollinators
Breast Cancer Awareness among Females in a Developing World - A Study from Kashmir
Background: Breast cancer is a major health issue and in developing
regions, where the early cancer detection facilities are unavailable
awareness about this disease can lead to early detection and thereby
potentially decrease the morbidity and mortality. Methods: A self
designed questionnaire was used to study the level of awareness
regarding breast cancer among 864 Kashmiri females. The questionnaire
had 18 questions and on the basis on score attained, the subjects were
classified as having poor, average or good breast cancer awareness.
Results: Out of 864 participants, 703(81.37%) had poor breast cancer
awareness and 103(11.92%) had average awareness. Only 58(6.71%) had
good awareness about breast cancer. Conclusion: The level of awareness
regarding breast cancer in Kashmiri females is very low and there is a
need to spread awareness about this disease among the general
population
Length-weight relationship and relative condition factor of Schizopyge esocinus (Heckel, 1838)
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