Majumder Ratna Rani, Sandhu Nitika, Yadav Shailesh, Catolos Margaret, Cruz Ma Teresa Sta, Maturan Paul Cornelio, Hassan Lutful, Hossain Mohammad Amir, Kumar Arvind
Rice Breeding Platform, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
Bangladesh Agricultural University, Mymensingh 2202, Dhaka, Bangladesh.
Curr Genomics. 2021 Dec 30;22(6):468-483. doi: 10.2174/1386207324666210713112127.
The aim of the present study was to evaluate the performance of 'high'-'low' yielding pyramided lines (PLs), having the same combinations of in Samba Mahsuri, MR219 and IR64-Sub1 genetic backgrounds, and to understand the genetic interactions among QTL and/with genetic background affecting grain yield.
Epistasis regulates the expression of traits governed by several major/minor genes/QTL. Multiple pyramided lines (PLs) with the same grain yield QTL () combinations but possessing grain yield variability under different levels of reproductive stage drought stress were identified in different rice genetic backgrounds at International Rice Research Institute (IRRI).
The objectives of the present study were to evaluate the performance pyramided lines (PLs) with drought QTL in the backgrounds of Samba Mahsuri, MR219 and IR64Sub1 under reproductive stage drought stress (RS) and NS (non-stress) conditions, to understand the effect of epistatic interactions among and with genetic background on GY under the differential level of stress and to identify the promising drought-tolerant lines with high yield under drought and higher background recovery in different genetic backgrounds.
The experiments were conducted in 2015 DS (dry season), 2015 WS (wet season) and 2017 DS at IRRI, Los Baños, Philippines, in a transplanted lowland ecosystem under lowland severe stress (LSS), lowland moderate stress (LMS) and lowland non-stress (LNS). The experiments were laid out in alpha lattice design with two replications.
Several digenic interactions were found in different genetic backgrounds, 13 interactions in Samba Mahsuri, 11 in MR219 and 20 in IR64-Sub1 backgrounds. Among all digenic interactions, one QTL × QTL interaction, 17 QTL × background and 26 background × background interactions resulted in GY reduction in low yielding PLs in different genetic backgrounds under LSS or LMS. Negative interaction of , and with background markers and background × background interactions caused up to 15% GY reduction compared to the high yielding PLs under LMS in the Samba Mahsuri PLs. In MR219 PLs, the negative interaction of , , and with the background marker interval RM314-RM539, RM273-RM349 and RM445-RM346, RM473D-RM16, respectively resulted 52% GY reduction compared to the high yielding PLs under LSS. In IR64-Sub1 PLs, interacted with background loci at RM16-RM135, RM228-RM333, RM202-RM287 and RM415-RM558A marker interval under LSS and at RM475-RM525 marker interval under LMS, causing GY reduction to 58% compared to the high yielding PLs.
High yielding PLs in Samba Mahsuri (IR 99734:1-33-69-1-22-6), MR219 (IR 99784-156-87-2-4-1) and IR64-Sub1 (IR 102784:2-89-632-2-1-2) backgrounds without any negative interactions were identified. The identified selected promising PLs may be used as potential drought-tolerant donors or may be released as varieties for drought-prone ecosystems in different countries.
本研究的目的是评估在桑巴马苏里、MR219和IR64 - Sub1遗传背景下具有相同基因组合的“高”产与“低”产聚合系（PLs）的表现，并了解影响谷物产量的数量性状基因座（QTL）之间以及与遗传背景之间的遗传相互作用。
上位性调控由多个主/微效基因/QTL控制的性状的表达。国际水稻研究所（IRRI）在不同水稻遗传背景中鉴定出了具有相同谷物产量QTL组合但在不同生殖阶段干旱胁迫水平下谷物产量存在差异的多个聚合系（PLs）。
本研究的目标是评估在生殖阶段干旱胁迫（RS）和非胁迫（NS）条件下，桑巴马苏里、MR219和IR64 - Sub1背景下具有干旱QTL的聚合系（PLs）的表现，了解在不同胁迫水平下QTL之间以及与遗传背景的上位性相互作用对谷物产量的影响，并在不同遗传背景中鉴定出在干旱条件下高产且背景回复率高的有前景的耐旱系。
试验于2015年旱季（DS）、2015年雨季（WS）和2017年DS在菲律宾洛斯巴尼奥斯的IRRI进行，在低地严重胁迫（LSS）、低地中度胁迫（LMS）和低地非胁迫（LNS）条件下的移栽低地生态系统中进行。试验采用α格子设计，重复两次。
在不同遗传背景中发现了几个双基因相互作用，在桑巴马苏里背景中有13个相互作用，在MR219背景中有11个，在IR64 - Sub1背景中有20个。在所有双基因相互作用中，一个QTL×QTL相互作用、17个QTL×背景和26个背景×背景相互作用导致不同遗传背景下低产PLs在LSS或LMS条件下谷物产量降低。在桑巴马苏里PLs中，与背景标记以及背景×背景相互作用的负相互作用导致在LMS条件下与高产PLs相比谷物产量降低高达15%。在MR219 PLs中，分别与背景标记区间RM314 - RM539、RM273 - RM349和RM445 - RM346、RM473D - RM16的负相互作用导致在LSS条件下与高产PLs相比谷物产量降低52%。在IR64 - Sub1 PLs中，在LSS条件下与RM16 - RM135、RM228 - RM333、RM202 - RM287和RM415 - RM558A标记区间以及在LMS条件下与RM475 - RM525标记区间的背景位点相互作用，导致与高产PLs相比谷物产量降低58%。
在桑巴马苏里（IR 99734:1 - 33 - 69 - 1 - 22 - 6）、MR219（IR 99784 - 156 - 87 - 2 - 4 - 1）和IR64 - Sub1（IR 102784:2 - 89 - 632 - 2 - 1 - 2）背景中鉴定出了没有任何负相互作用的高产PLs。所鉴定出的有前景的PLs可作为潜在的耐旱供体，或可作为不同国家易旱生态系统的品种发布。
