Introgression of Root and Water Use Efficiency Traits Enhances Water Productivity: An Evidence for Physiological Breeding in Rice (Oryza sativa L.)

Rice

Table 3 Morpho-physiological and molecular variations of IR-64 and the backcross progenies at different generations (A) mean and range for the phenotypic value of target traits (B) improvement in traits over IR-64 at each generations, number of markers introgressed and background genome recovery in advanced backcross stages

(A)
Generation	Season	# of plants		Δ¹³C (‰)				LT (° C)
Generation	Season	# of plants		IR-64	Mean ± SD	Range		IR-64	Mean ± SD	Range
BC₁F₁ ^a	June–December,2012	42		21.5	21.23 ± 0.95	17.5–25.5		35.6	32.3 ± 2.04	32.4–36.4
BC₂F₁	June–December,2014	100		21.88	19.7 ± 0.87	18–25.3		37.2	35.0 ± 1.87	31.4–36.52
BC₃F₁	January–May, 2015	120		22.65	18.84 ± 0.93	15.09–20.62		36.3	34.34 ± 1.73	30.2–36.5
(B)
Generation	Plants selected	# of markers in heterozygote condition		Genome recovery (%)		Phenotype		% change over IR-64		Significance
Generation	Plants selected	Roots (12)	Δ¹³C (4)	Expected	Estimated	Δ¹³C	LT	Δ¹³C (−ve)	LT (−ve)	Δ¹³C	LT
BC₁F₁	32	12	4	75.0	72.5	19.5	32.1	9.30	9.83	**	*
	73	11	3	75.0	69.7	19.1	33.5	11.16	5.90
	81	12	4	75.0	70.4	19.8	32.5	7.91	8.71
	91	11	2	75.0	73.2	19.4	34.1	9.77	4.21
BC₂F₁	32–1	12	4	87.5	83.2	18.28	31.6	16.45	15.05	**	**
	73–3	10	3	87.5	82.8	18.65	33.2	14.76	10.75
	81–23	12	4	87.5	82.1	18.42	31.4	15.81	15.59
BC₃F₁	32–1-34	11	3	93.75	90.5	19.96	32.1	11.88	11.57	**	**
	32–1-40	10	4	93.75	90.5	18.35	31.5	18.98	13.22
	81–23-27	10	3	93.75	91.5	17.82	32.7	21.32	9.92
	81–23-31	10	4	93.75	92.5	18.85	31.1	16.78	14.33

Δ¹³C Carbon isotope discrimination (‰), LT Leaf temperature (°C)
^a Since this was an early generation only 42 BC₁F₁ plants were phenotyped out of the total 120 BC₁F₁ plants generated
* and ** denote significance at 5% and 1%, respectively