Dhaka University Scientists in collaboration with BRRI plant breeders produce salt tolerant versions of commercial rice BRRI Dhan 63 and 74 and highly salt tolerant version of BRRI Dhan 67 in 2.5 years by use of fluorescent DNA markers and real time PCR. The new technique is called KASP or Kompetitive Allele Specific PCR.
Use of KASP genotyping technology allowed the team to incorporate 3 salt-tolerant genetic loci (QTLs) from Salt-tolerant landrace Horkuch through marker assisted breeding into BR63, BR67 and BR74 variety in the very short period of 2.5 years. Before undertaking this project, 14 QTLs from salt-tolerant landrace Horkuch were identified (https://www.biorxiv.org/content/10.1101/2020.03.01.971895v1). Enhanced Root Length locus from Chromosome 2, Potassium ion retention locus from Chromosome 3 and Saltol locus on Chromosome 1 present in Horkuch were selected as the target regions to be introduced into commercial rice. BRRI dhan63, BRRI dhan67 and BRRI dhan74 were selected as the recipient parents. All 3 recipient parents already had the allele for the yield trait. The three target loci were transferred from 2 progenies called RILs of the Horkuch×IR29 population. These RILs are I-14 containing the Root length locus and shoot K+ locus and I-71 containing the Saltol QTL locus. According to the conventional breeding process at first each background parent (commercial rice) was crossed separately with the 2 RILs. The 2 progenies produced (F1s) which were then crossed between themselves, so that all 3 QTLs were now in the double F1 progenies. Each was separately backcrossed twice with each of the background high yielding parents using fluorescent markers to select the progenies possessing the desired alleles. As a result, salt tolerant versions of BRRI Dhan 63 and BRRI Dhan 74 were produced. Highly salt tolerant version of BRRI Dhan 67 was also produced since BR67 already possessed one mechanism of salt tolerance.
The DNA marker work for progeny selection was done under the mentorship of Dr. Zeba Islam Seraj of the Department of Biochemistry and Molecular Biology and the students involved in the work were, Tomalika Azim, Yeamin Farabi Ria and GM Nurnabi Azad Jewel. Mr. Rezaul Karim of BCSIR was a collaborator for the real Time PCR work.
The breeding was done by Dr. M. Ruhul Amin Sarker, Dr. Sazzadur Rahman, Dr. M A Rahman and Dr. Hosne Ara Hossain under the Research Directorship of Dr. Khandekar Iftekharuddowla of Bangladesh Rice Research Institute.
The work was funded by NATP2 under the World Bank.