Variation among wheat (Triticum easativum L.) genotypes in response to the drought stress: I – selection approaches

Figures & data

Table 1. Dry matter (DM) and grain yield (GY) of 20 wheat genotypes grown under control (C) and drought stress (D) and ANOVA analyze of variance.

No	Genotype	Dry matter (DM-g plant^−1)			Grain yield (GY-g plant^−1)
		Control (C)	Drought (D)	RTC	Control (C)	Drought (D)	RTC
1	Telimena	1.52 m	0.59 abcd	0.61	0.89 de	0.01 a	0.98
2	Arabella	1.26 hijk	0.58 abcd	0.54	1.07 f	0.35 d	0.67
3	Mandaryna	1.28 ijkl	0.60 abcd	0.53	1.08 f	0.43 de	0.60
4	Sirocco	1.61 n	0.60a bcd	0.63	0.96 def	0.12 bc	0.87
5	Sharki	1.02 bc	0.58a bcd	0.43	0.76 c	0.08 ab	0.59
6	Cornetto	1.06 cd	0.57 abcd	0.46	0.71 bc	0.11 b	0.60
7	Tybalt	1.09 cde	0.52 ab	0.52	0.80 cd	0.37 d	0.60
8	Goplana	1.30 jkl	0.52 ab	0.60	0.92 de	0.19 bc	0.79
9	Harenda	1.17 fg	0.62 bcd	0.47	0.77 c	0.47 e	0.56
10	Kandela	1.20 ghij	0.59 abcd	0.51	0.91 de	0.49 e	0.58
11	Struna	1.21 ghij	0.89 ef	0.26	0.94 de	0.57ef	0.41
12	Jarlanka	1.10 cdef	0.51 ab	0.54	0.86 d	0.39 d	0.55
13	SMJ 2115	0.95 ab	0.71d	0.25	0.87 de	0.59 f	0.32
14	SMJ 3016	1.25 ghij	0.56 ab	0.55	0.51bc	0.23 c	0.55
15	SMJ 1314	1.32 jkl	0.70 cd	0.47	0.78 c	0.39 d	0.50
16	Ostka smolicka	1.19 gh	0.60 abcd	0.50	0.59 bc	0.34 d	0.49
17	Tdoz 1384	0.92 a	0.47 a	0.49	0.32 a	0.16 bc	0.49
18	Tdoz 1403	1.68 n	0.81d	0.52	0.99 def	0.03a	0.97
19	Tdzo 1508	1.21 ghij	1.05 e	0.13	0.80 cd	0.49 e	0.39
20	Tonika	1.68 n	1.02 e	0.39	0.79 cd	0.11b	0.86
Mean		1,25	0.65	0.47	0.82	0.29	0.62
CV (%)		17,7	25.2	26.7	25.2	63.7	34.5
Anova
Variable	df	Dry matter (DM)		Grain yield (GY)
		C	D	C	D
Genotype (G) Treatment (T) G × T	19 1 19	** * *	*** * *	** NS *	** * *

Notes: CV – coefficient of variation; df – number of freedom degree. Different letters in column indicate significant differences according Duncan test at p < .05 level. Based on decrease of relative traits changes (RTC) of DM or GY, the genotypes are divided into four groups: Light grey (>0.30), Medium grey (<0.30 > 0.50), Dark Grey (<0.50 > 0.70) and Normal Grey (>0.70). *, **, *** – statistical significance at level p < .1, .05, .01, respectively. NS – no significant differences.

Figure 1. Changes of daily maximum and minimum air temperature (a), air relative humidity RH (b) and growth degree days GDD (c). Red line on x-axis marks the period of drought.

Table 2. Mean values, range of mean, LSD_0,05, and coefficient of variation (CV) for the physiological traits of wheat genotypes grown in control (C) and drought (D) conditions.

Traits	Control (C)				Drought (D)
	Mean	Range	LSD0,05V	CV (%)	Mean	Range	LSD0,05V	CV (%)
Traits measured directly after drought
DM – Biomass dry matter (g plant^−1) H – Seedlings height (cm) NoT – Number of tillers NoLMT – No. of leaves on main tiller NoLAT – No of leaves on adventitious tillers NoLT – Total leaf number SPAD – Leaf greening	1.25 36.6 2.3 5.8 7.4 13.2 19.0	0.92–1.68 28.3–51.6 1.3–3.1 4.3–6.4 4.3–10.0 10.4–16.1 14.5–26.2	0.39 3.89 0.49 0.88 2.18 1.07 3.11	26.9 16.5 21.0 8.1 19.1 10.5 15.8	0.65 23.2 1.6 6.1 4.7 10.8 12.7	0.51 - 1.02 17.0–31.6 0.9–2.8 4.5–7.2 2.1–9.6 8.3–15.6 7.7–20.3	0.13 1.80 0.41 1.11 2.39 2.13 3.18	37.8 17.6 33.6 10.6 42.6 19.2 26.6
Traits measured after harvesting
GY – Grain weight (g plant^−1) NoG – Number of grain W-1000 – Weight of 1000 grain (g plant^−1)	0.81 27.0 31.0	0.32–1.08 7.8–38.7 23.5–43.3	0.08 3.07 5.55	25.2 29.4 17.0	0.30 13.1 22.9	0.01–0.11 1.1–20.5 9.6–37.0	0.07 4.18 5.05	55.4 48.4 33.0

Table 3. Relative change of measured traits (RTC), mean values, LSD_0.05, coefficient of variation (CV) and correlation coefficient for traits of 20 wheat genotypes.

No.	Genotype	DM	GY	H	NoT	Leaf number			SPAD	Grain
						NoLMT	NoLAT	NoLT		NoG	W-1000
1	Telimena	0.61	0.98	0.50	0.57	0.07	0.57	0.36	0.49	0.96	0.60
2	Arabella	0.54	0.67	0.33	0.43	−0.12	0.53	0.31	0.18	0.65	0.08
3	Mandaryna	0.53	0.60	0.56	0.12	0.30	0.88	0.25	0.20	0.60	0.02
4	Sirocco	0.63	0.87	0.50	0.50	−0.12	0.46	0.22	0.33	0.86	0.08
5	Sharki	0.43	0.59	0.29	0.47	−0.24	0.88	0.19	0.46	0.57	0.06
6	Cornetto	0.46	0.60	0.37	0.67	−0.07	0.70	0.35	0.06	0.53	0.16
7	Tybalt	0.52	0.60	0.36	0.54	−0.04	0.59	0.34	0.29	0.45	0.27
8	Goplana	0.60	0.79	0.49	0.46	−0.10	0.54	0.27	0.37	0.71	0.28
9	Harenda	0.47	0.56	0.35	0.28	0.03	0.38	0.20	0.34	0.24	0.42
10	Kandela	0.51	0.58	0.32	0.41	−0.07	0.43	0.22	0.20	0.29	0.41
11	Struna	0.26	0.41	0.26	0.08	−0.03	−0.12	−0.08	0.04	0.45	−0.08
12	Jarlanka	0.54	0.55	0.31	0.48	−0.26	0.58	0.21	0.34	0.31	0.34
13	SMJ 2115	0.25	0.32	0.12	−0.46	0.02	0.05	0.03	0.30	0.34	−0.02
14	SMJ 3016	0.55	0.55	0.27	−0.13	0.03	0.51	0.30	−0.03	−0.68	0.73
15	SMJ 1314	0.47	0.50	0.35	0.23	−0.28	0.43	0.16	0.49	0.35	0.23
16	Ostka smolicka	0.50	0.49	0.41	0.19	−0.09	0.18	0.06	0.50	−0.08	0.53
17	Tdoz 1384	0.49	0.49	0.37	0.45	−0.06	0.61	0.32	0.51	0.44	0.10
18	Tdzo 1403	0.52	0.97	0.41	0.00	0.00	0.01	0.01	0.65	0.93	0.51
19	Tdoz 1508	0.13	0.39	0.25	−0.18	0.03	−0.30	−0.15	0.17	0.52	−0.27
20	Tonika	0.39	0.86	0.33	0.10	0.05	0.20	0.14	0.51	0.73	0.49
Mean		0.47	0.62	0.36	0.26	−0.05	0.41	0.18	0.32	0.46	0.25
L.S.D (0.05)		0.13	0.18	0.11	0.08	0.07	0.25	0.12	0.10	0.33	0.39
% CV		26.7	30.0	28.5	113.2	−272.8	77.2	78.0	57.2	80.4	103.9
Correlation coefficient
Trait	GY	H	NoT	NoLMT	NoLAT	NoLT	SPAD	NoG	W-1000
	2	3	4	5	6	7	8	9	10
1 – DM	0.634***	0.717***	0.638***	−0.118^NS	0.690***	0.774***	0.231 ^NS	0.077 ^NS	0.591***
2 – GY		0.657***	0.401*	0.114 ^NS	0.219 ^NS	0.358 ^NS	0.444**	0.602***	0.480**
3 – H			0.538**	0.134 ^NS	−0.246 ^NS	−0.081 ^NS	−0.092 ^NS	0.026 ^NS	−0.033 ^NS
4 – NoT				−0.395*	0.670***	0.702***	0.127 ^NS	0.331 ^NS	0.134 ^NS
5 – NoLMT					−0.120 ^NS	−0.048 ^NS	−0.226 ^NS	0.054 ^NS	0.025 ^NS
6 – NoLAT						0.869***	−0.002 ^NS	0.010 ^NS	0.173 ^NS
8 – NoLT							−0.040 ^NS	0.001 ^NS	0.373 ^NS
9 – SPAD								0.427**	0.283 ^NS
10 – NoG									−0.312 ^NS

Notes: *, **, *** – statistical significance for correlation coefficient at level p < .50, .10 and .01, respectively. NS – not significant differences.

Table 4. Drought tolerance indexes calculated for dry biomass of above-ground plant part (DM) and grain yield (GY) of 20 wheat genotypes grown in control (C) and drought (D) conditions and analyze of variance ANOVA.

No	Genotype	Based on biomass dry matter (DM) of above-ground plant part							Based on grain yield (GY)
		DSI	STI	MPRO	MHAR	TI	GMP	SI	DSI	STI	MPRO	MHAR	TI	GMP	SI
1	Telimena	1.291	0.571	1.054	0.845	0.938	0.944	0.384	1.552	0.019	0.452	0.027	0.876	0.111	0.016
2	Arabella	1.126	0.471	0.922	0.798	0.677	0.858	0.463	1.063	0.569	0.708	0.524	0.719	0.609	0.326
3	Mandaryna	1.116	0.491	0.939	0.816	0.681	0.875	0.467	0.951	0.704	0.751	0.611	0.649	0.678	0.397
4	Sirocco	1.316	0.619	1.105	0.874	1.011	0.983	0.372	1.373	0.184	0.544	0.221	0.838	0.346	0.130
5	Sharki	0.909	0.380	0.801	0.740	0.444	0.770	0.567	0.933	0.362	0.421	0.145	0.450	0.247	0.409
6	Cornetto	0.974	0.386	0.814	0.740	0.493	0.776	0.536	0.952	0.303	0.406	0.185	0.426	0.274	0.397
7	Tybalt	1.101	0.361	0.803	0.701	0.572	0.750	0.475	0.949	0.389	0.583	0.504	0.480	0.542	0.398
8	Goplana	1.262	0.431	0.908	0.740	0.782	0.820	0.398	1.253	0.266	0.555	0.314	0.731	0.417	0.205
9	Harenda	0.981	0.470	0.900	0.816	0.550	0.857	0.532	0.884	0.400	0.622	0.586	0.432	0.604	0.440
10	Kandela	1.064	0.455	0.896	0.792	0.609	0.842	0.493	0.918	0.529	0.698	0.635	0.529	0.666	0.418
11	Struna	0.554	0.692	1.051	1.027	0.320	1.039	0.736	0.650	0.849	0.755	0.710	0.400	0.732	0.588
12	Jarlanka	1.125	0.360	0.805	0.697	0.590	0.749	0.464	0.860	0.512	0.624	0.536	0.468	0.578	0.455
13	SMJ 2115	0.524	0.432	0.829	0.812	0.237	0.820	0.751	0.508	0.781	0.727	0.701	0.279	0.714	0.678
14	SMJ 3016	1.158	0.445	0.901	0.770	0.688	0.833	0.447	0.865	0.076	0.338	0.338	0.182	0.338	0.452
15	SMJ 1314	0.978	0.593	1.010	0.916	0.614	0.962	0.534	0.784	0.468	0.585	0.521	0.387	0.552	0.503
16	Ostka smolicka	1.038	0.457	0.894	0.797	0.588	0.844	0.505	0.781	0.273	0.465	0.430	0.294	0.447	0.505
17	Tdzo 1384	1.033	0.276	0.694	0.620	0.454	0.656	0.507	0.774	0.079	0.240	0.214	0.156	0.227	0.509
18	Tdoz 1403	1.086	0.876	1.248	1.095	0.872	1.169	0.482	1.526	0.048	0.510	0.061	0.956	0.177	0.032
19	Tdoz 1508	0.273	0.812	1.128	1.123	0.157	1.125	0.869	0.616	0.601	0.646	0.608	0.313	0.626	0.610
20	Tonika	0.824	1.098	1.350	1.269	0.660	1.309	0.607	1.362	0.131	0.450	0.190	0.684	0.293	0.136
Mean		0.987	0.530	1.578	0.849	0.597	0.899	0.529	0.978	0.377	0.552	0.408	0.512	0.463	0.380
CV (%)		16.9	19.1	36.1	17.8	17.8	25.2	23.9	30.0	65.8	26.2	49.2	44.8	39.7	49.0
ANOVA
Genotype (G) Treatment (T) G × T	19 1 19	*** ** **	* NS *	** NS NS	* * *	* * NS	*** ** *	** * NS	*** ** *	* NS NS	* NS NS	* * *	* * NS	** * *	* * NS

Notes: *, **, *** – statistical significance at level p < .1, .05, .01, respectively. NS – no significant differences.

Table 5. Linear correlation coefficient between different drought tolerance indexes of wheat genotypes (df = 18).

No	Indexes	STI	MPRO	MHAR	TI	GMP	SI
Based on dry matter (DM)
1	DSI	−0.342 ^NS	0.025 ^NS	−0.481**	0.874***	−0.335 ^NS	−0.999***
2	STI		0.917***	0.985***	0.118***	0.995***	0.341 ^NS
3	MPRO			0.854***	0.491**	0.929***	−0.026 ^NS
4	MHAR				−0.030 ^NS	0.986***	0.480**
5	TI					0.136 ^NS	−0.875***
6	GMP						0.335 ^NS
Based on grain yield (GY)
1	DSI	−0.673***	−0.250 ^NS	−0.794***	0.886***	−0.688***	−0.999***
2	STI		0.872***	0.969***	−0.272 ^NS	0.980***	0.673***
3	MPRO			0.766***	0.218 ^NS	0.848***	0.250 ^NS
4	MHAR				−0.446**	0.986***	0.794***
5	TI					−0.301 ^NS	−0.886***
6	GMP						0.688***

Notes: *, **, *** – statistical significance for correlation coefficient at level p < .50, .10 and .01, respectively. NS – not significant differences.

Figure 2. Principal component analysis (PCA) for physiological traits (a) and genotypes (b) based on stress indexes calculated for physiological traits.

Figure 3. Principal component analysis (PCA) of drought tolerance indexes for (a) dry biomass (DM) and (b) genotypes.

Figure 4. Dendrogram of 20 wheat genotypes resulting from cluster analysis (Ward’s methods) of stress index (SI) calculated for physiological traits (a) and drought tolerance indexes (b).

Figure 5. The photographs of 11-week-old wheat plants grown in control (C) or drought (D) conditions. Telimena, Sirocco and Goplana were selected as drought-sensitive genotypes and Struna, SMJ 2115 and Tdoz 1508 as drought-resistant genotypes.

Table 6. Membrane injury (LI), leaf water status (RWC, RT, WD) and linear correlation coefficient for 6 wheat genotypes. Mean values (n = 5) ± SE (df = 4).

Genotype	Treatments	Electrolyte leakage			Leaf water status
		Initial (µS gfw^−1)	Final (µS gfw^−1)	LI (%)	RWC (%)	RT (%)	WD (%)
Drought sensitive genotypes
Telimena	Control	12.2 ±1.0	190.2 ±8.5	23.0 ±3.2	73.2 ±2.9	85.9 ±2.1	14.1 ±2.1
	Drought	37.3 ±2.6	133.3 ±6.7		69.7 ±1.3	64.1 ±3.3	35.9 ±3.3
	% control	304.5	70.1		95.3	74.6	255.1
Sirocco	Control	12.4 ±1.4	167.8 ±2.1	21.6 ±1.6	72.0 ± 3.2	72.9 ± 2.6	27.1 ± 2.2
	Drought	55.1 ±2.3	201.6 ±11.9		58.8 ± 2.9	62.6 ± 3.1	41.2 ± 1.8
	% control	446.1	120.2		81.7	85.9	152.0
Goplana	Control	13.0 ±1.4	208.6 ±2.5	21.3 ±2.7	70.7 ±4.5	77.0 ±2.9	23.0 ±2.9
	Drought	49.8 ±3.0	189.8 ±11.6		65.0 ±5.0	55.6 ±2.1	44.4 ±2.1
	% control	382.9	91.0		91.9	72.2	193.3
Mean	Control	12.5	188.9	22.2	72.0	78.6	21.4
	Drought	47.4	174.9		64.5	60.8	40.5
	% control	378.2	92.6		89.6	77.3	189.3
Drought-resistant genotypes
Struna	Control	15.3 ±1.8	141.5 ±5.2	11.0 ±1.5	77.6 ±2.4	80.8 ±1.7	19.2 ±1.7
	Drought	39.1 ±0.5	189.2 ±4.5		69.0 ±1.0	67.9 ±3.2	32.1 ±3.2
	% control	255.3	133.7		88.9	84.1	166.9
SMJ 2115	Control	16.3 ±0.7	186.2 ±6.6	12.9 ±2.1	75.2 ±3.3	80.3 ±2.3	19.7 ±2.3
	Drought	42.1 ±3.1	205.3 ±11.9		67.0 ±4.4	64.7 ±1.4	35.3 ±1.4
	% control	258.2	110.3		89.1	80.5	179.2
Tdoz 1508	Control	12.2 ±0.1	177.6 ±5.7	12.3 ±2.9	77.5 ±2.4	85.7 ±1.7	14.3 ±1.7
	Drought	45.8 ±5.3	249.7 ±22.0		66.0 ±3.4	75.4 ±2.9	24.6 ±2.9
	% control	374.1	140.6		85.2	88.0	171.9
Mean	Control	14.6	168.4	12.2	76.8	82.3	17.7
	Drought	42.3	214.7		67.3	69.3	30.7
	% control	289.5	127.5		87.7	84.3	172.9

Correlation coefficient r (df = 4)
Indexes/Traits	RWC	RT	WD	DM	GY	DSI	STI	MPRO	MHAR	TI	GMG
LI	0.276^NS	−0.605^NS	0.503^NS	−0.957***	−0.969***	0.806*	−0.265^NS	−0.086^NS	−0.273^NS	0.707^NS	−0.182^NS
RWC		−0.849**	0.872**	−0.247^NS	−0.272^NS	0.504^NS	0.268^NS	0.361^NS	0.239^NS	0.585^NS	0.301^NS
RT			−0.719^NS	0.598^NS	0.522^NS	−0.702^NS	−0.184^NS	−0.328^NS	−0.183^NS	−0.718^NS	−0.256^NS
WD				−0.387^NS	−0.520^NS	0.576^NS	−0.106^NS	0.023^NS	−0.148^NS	0.591^NS	−0.064^NS

Notes: *, **, *** – statistical significant correlation coefficient at level p < .5, .1 and .01, respectively, NS – not significant differences.