Recovery of Recurrent Parent Genome in a Marker-Assisted Backcrossing Against Rice Blast and Blight Infections Using Functional Markers and SSRs.

Samuel Chibuike Chukwu,Isma’Ila Muhammad,Siti Izera Ismail,Shairul Izan Ramlee,Bashir Rini Yusuf,Ibrahim Musa,Muideen Ahmed,Mohd Y Rafii,Muhammed Itopa Jatto,Yusuff Oladosu

doi:10.3390/plants9111411

Samuel Chibuike Chukwu, Isma’Ila Muhammad + Show 8 more

Open Access

https://doi.org/10.3390/plants9111411

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Abstract

The most vital aspect of marker-assisted backcross breeding is the recurrent parent genome recovery. This enables the selection of only parents with recovered recipient/recurrent parent genome in addition to the targeted genes. The recurrent parent genome recovery (RPGR) ensures that non-desirable genomic segments are removed while the gene of interest is sustained in the recombined progenies without further segregations. This work was aimed at quantifying the RPGR of backcross populations with introgression of bacterial leaf blight resistance genes. Putra-1, a Malaysian elite variety, high yielding with inherent resistance to blast but susceptible to bacterial leaf blight (BLB), was crossed with IRBB60 which is resistant to BLB disease. The IRBB60 has four Xoo resistance genes—Xa4, xa5, xa13 and Xa21. Tightly linked polymorphic functional and SSR markers were used for foreground selection at every stage of backcrossing to select progenies with introgressed target genes. Background selection was done to quantify the percentage of RPGR in the selected lines using 79 confirmed polymorphic microsatellites. Result obtained showed that the percentage of RPGR was 80.11% at BC1F1, 95.30% at BC2F1 and 95.9% at BC2F2. The introgression of Xa4, xa5, xa13 and Xa21 Xoo resistance genes were faster through the adopted marker-assisted backcross breeding compared to what could be obtained through conventional breeding. All the 16 selected lines displayed resistance to BLB with three lines showing high resistance to the disease. The blast resistance contained in the genetic background of Putra-1 was also sustained in all the selected lines. The newly developed lines were recommended as new rice varieties for commercial cultivation.

Highlights

Rice is an important cereal crop that plays a critical role in human diet [1,2]
This work showed that marker-assisted backcross breeding is a useful tool for introgression of resistance genes from the donor parent into the recipient
It revealed the potentials of foreground selection in identifying the target genes for resistance of bacterial leaf blight and blast infections

Summary

Introduction

Most rice production takes place in the Asian continent with over 150 million ha cultivated all over the world [1,3]. Plants 2020, 9, 1411 favorable environmental condition, the rice crops would grow fast and produce high yields [4]. It does well in saline water with a high enough quantity of micronutrients. The availability of irrigation facilities and its further expansion, provision of subsidy for machineries, fertilizer, seeds, irrigation, as well as new technologies would lead to increased productivity of rice in various agricultural areas [5]. Singh et al [6] reported that there will be over eight billion people in the world by 2030 and the population is further predicted to reach nine billion by 2050

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