Physiological mechanisms contributing to the QTL qDTY3.2 effects on improved performance of rice Moroberekan x Swarna BC2F3:4 lines under drought

Rice

Table 2 Correlation of shoot- and root-growth related traits with grain yield across field experiments under well-watered and drought stress conditions

Treatment	Trait	Correlation with grain yield
Treatment	Trait	13DS	13WS (E)	13WS (L)	14DS (E)	14DS (L)	14WS	15DS
Well-watered	Tiller	0.1450	−0.0776	0.2274	0.2458	0.3289*	0.1768	0.1157
	DTF	−0.0688	−0.2478	−0.1718	0.1065	0.1072	0.166	0.1315
	SDM	0.631***	0.204	0.2097	0.4034*	0.0418	0.3628*	n.a.
	RLD (0–30)	n.a.	−0.1263	0.3543*	0.4301**	0.4663**	0.2656	0.1914
	RLD (30–60)	n.a.	−0.1396	0.0758	0.1021	0.1387	0.0851	−0.1768
	% shallow roots	n.a.	0.059	0.0236	0.1857	0.1313	0.147	0.3629
	% deep roots	n.a.	−0.059	−0.0236	−0.1857	−0.1313	−0.147	−0.3629
Drought stress	Tiller	0.0375***	−0.1439	−0.366*	−0.6481***	−0.7027***	0.1083	−0.0395
	CT	−0.4981***	−0.0487	−0.0184	−0.2379	−0.3107	0.0971	−0.4983*
	DTF	−0.5695*	−0.5117**	−0.4434**	0.247	−0.2042	−0.244	−0.2469
	SDM	0.2439**	−0.203	0.1347	−0.1086	0.1957	0.1326	n.a.
	RLD (0–30)	−0.3528*	0.2557	0.0307	−0.0156	−0.5285***	0.4113*	−0.2872
	RLD (30–60)	0.3048*	0.1509	0.1267	0.6523***	0.4814**	−0.1126	−0.1282
	% shallow roots	−0.5077***	0.0523	−0.1381	−0.438**	−0.7437***	0.4684**	−0.0896
	% deep roots	0.5077***	−0.0523	0.1381	0.438**	0.7437***	−0.4684**	0.0896

Traits measured on the BC₂F_3:4 lines included the well-watered and drought stress treatments of Experiments 13DS, 13WS (E), 13WS (L), 14DS (E), 14DS (L), 14WS and 15DS were used for Pearson correlation test. Tiller: number of tiller; CT: canopy temperature; DTF: time to flowering; SDM: shoot dry mass; RLD (0–30): root length density from 0 to 30 cm; RLD (30–60): root length density from 30 to 60 cm; % shallow roots: percentage of root length from 0 to 30 cm; % deep roots: percentage of root length from 30 to 60 cm. Values indicate the Pearson’s coefficient of correlation. *p-values < 0.05; **p-values < 0.01; ***p-values < 0.001. n.a.: not applicable because the trait was not measured in the experiment