ABSTRACT
This study was carried out to improve the RPHR-1005, a stable restorer line of the popular medium slender grain type rice hybrid, DRRH-3 for bacterial blight (BB) and blast resistance through marker-assisted backcross breeding (MABB). Two major BB resistance genes, Xa21 and Xa33 and a major blast resistance gene, Pi2 were transferred to RPHR-1005 as two individual crosses. Foreground selection for Xa21, Xa33, Pi2, Rf3 and Rf4 was done by using gene-specific functional markers, while 59 simple sequence repeat (SSR) markers polymorphic between the donors and recipient parents were used to select the best plant possessing target resistance genes at each backcross generation. Backcrossing was continued till BC2F2 and a promising homozygous backcross derived line possessing Xa21+ Pi2 and another possessing Xa33 were intercrossed to stack the target resistance genes into the genetic background of RPHR-1005. At ICF4, 10 promising lines possessing three resistance genes in homozygous condition along with fine-grain type, complete fertility restoration, better panicle exertion and taller plant type (compared to RPHR-1005) were identified.
Subject(s)
Bacteria , Disease Resistance/genetics , Genetic Markers , Oryza/genetics , Plant Diseases/genetics , Plant Diseases/microbiology , Breeding , Genes, Plant , Genotype , Hybridization, Genetic , Microsatellite Repeats , Phenotype , Selection, GeneticABSTRACT
RPHR-1005, the stable restorer line of the popular medium slender (MS) grain type rice hybrid, DRRH-3 was improved in this study for resistance against bacterial blight (BB) and blast diseases through marker-assisted backcross breeding (MABB). In this study, four major resistance genes (i.e., Xa21 and Xa33 for BB resistance and Pi2 and Pi54 for blast resistance) have been transferred to RPHR-1005 using RPBio Patho-1 (possessing Xa21 + Pi2), RPBio Patho-2 (possessing Xa21 + Pi54) and FBR1-15EM (possessing Xa33) as the donors. Foreground selection was carried out using PCR-based molecular markers specific for the target resistance genes and the major fertility restorer genes, Rf3 and Rf4, while background selection was carried out using a set of parental polymorphic rice SSR markers and backcrossing was continued uptoBC2 generation. At BC2F2, plants possessing the gene combination- Xa21 + Pi2, Xa21 + Pi54 and Xa33 in homozygous condition and with >92% recovery of the recurrent parent genome (RPG) were identified and intercrossed to combine all the four resistance genes. Twenty-two homozygous, pyramid lines of RPHR-1005 comprising of three single-gene containing lines, six 2-gene containing lines, eight 3-gene containing lines, and five 4-gene containing lines were identified among the double intercross lines at F3 generation (DICF3). They were then evaluated for their resistance against BB and blast, fertility restoration ability and for key agro-morphological traits. While single gene containing lines were resistant to either BB or blast, the 2-gene, 3-gene, and 4-gene pyramid lines showed good level of resistance against both and/or either of the two diseases. Most of the 2-gene, 3-gene, and 4-gene containing pyramid lines showed yield levels and other key agro-morphological and grain quality traits comparable to the original recurrent parent and showed complete fertility restoration ability, with a few showing higher yield as compared to RPHR-1005. Further, the experimental hybrids derived by crossing the gene-pyramid lines of RPHR-1005 with APMS6A (the female parent of DRRH-3), showed heterosis levels equivalent to or higher than DRRH-3. The results of present study exemplify the utility of MABB for targeted improvement of multiple traits in hybrid rice.
ABSTRACT
Haritaki is praised as the best salutary drug which can be used in almost all ages of human life and is reputed for its Anulomana property. In Ayurveda, it has been mentioned that fruits of Haritaki when used in different forms give different type of actions. As the prime therapeutic utility of Haritaki is Anulomana, in the present study, two dosage forms of Haritaki fruits namely Churna and Vati were evaluated for intestinal transit time to evaluate its effect in two different dosage forms. Mature fruits were collected, authenticated, and processed as per classics to get Churna and Vati. Test drugs were administered in the dose of 550 mg/kg and evaluation on intestinal transit time was carried out by adopting kaolin expulsion test in mice. The results show that both the dosage forms of Haritaki significantly shortened intestinal transit time and between them Churna form is found to be better.
ABSTRACT
Many concepts in Ayurveda are untouched or unexplored till date. One of such concepts to understand the healthy and unhealthy persons is that of the Aaturaparijnana Hetawah (APH), which is only mentioned in Caraka Samhita. The descriptions about Dushya, Desha, Bala, Kala, Prakriti, etc. are mentioned very briefly in all the classics. But no standard figure or pattern is maintained while considering them. It is only in the description of Aaturaparijnana Hetawah mentioned in Vimana Sthana that all the factors are pre-arranged in a chronological order to understand an individual according to one's Desha as from birth till grown up stage, and also to understand about the illness and most common disorders. In this article, it is aimed at presenting an in-depth evaluation about description of Aaturaparijnana Hetawah in Ayurveda. For this study, the references of Aturaparijnana Hetu have been collected through the Ayurvedic texts along with their commentaries. By making use of 14 factors described in Aaturaparijnana Hetawah, it is possible to have an in depth understanding about the patient's nature and factors that may be contributing to his health and illness. Aaturaparijnana Hetawah helps in an in-depth understanding of a patient's disease and heath status. More in-depth evaluation studies and application in the modern medical science should be done in order to avail the benefits of this approach.
