Inheritance of summer stress tolerance in tall fescue

Trent M. Tate; James W. Cross; Ruying Wang; Stacy A. Bonos; William A. Meyer; Trent M. Tate; James W. Cross; Ruying Wang; Stacy A. Bonos; William A. Meyer

doi:10.48130/GR-2023-0014

Cross/ parent	Female × male^a	Number of progeny	Progeny/ parent mean^b	SD
1	TF-2 × TF-5 (S × T)	96	5.5	0.8
2	TF-2 × TF-6 (S × T)	95	4.1	0.9
3	TF-2 × TF-10 (S × T)	96	4.3	1.0
4	TF-2 × TF-15 (S × S)	96	4.7	0.6
5	TF-2 × TF-21 (S × S)	96	3.4	0.3
6	TF-5 × TF-2 (T × S)	96	6.0	1.0
7	TF-5 × TF-6 (T × T)	96	5.3	1.5
8	TF-5 × TF-10 (T × T)	96	5.5	1.1
9	TF-5 × TF-15 (T × S)	96	6.0	0.7
10	TF-5 × TF-21 (T × S)	96	6.1	0.9
11	TF-6 × TF-2 (T × S)	95	4.1	0.5
12	TF-6 × TF-5 (T × T)	95	5.1	1.6
13	TF-6 × TF-10 (T × T)	96	4.6	0.9
14	TF-6 × TF-15 (T × S)	96	5.1	0.5
15	TF-6 × TF-21 (T × S)	96	3.3	0.5
16	TF-10 × TF-2 (T × S)	90	4.5	2.1
17	TF-10 × TF-5 (T × T)	96	5.3	0.7
18	TF-10 × TF-6 (T × T)	96	4.4	0.6
19	TF-10 × TF-15 (T × S)	91	4.2	0.8
20	TF-10 × TF-21 (T × S)	76	3.7	0.9
21	TF-15 × TF-2 (S × S)	91	5.0	1.1
22	TF-15 × TF-5 (S × T)	95	6.3	1.5
23	TF-15 × TF-6 (S × T)	96	5.2	0.8
24	TF-15 × TF-10 (S × T)	63	4.5	1.0
25	TF-15 × TF-21 (S × S)	96	4.9	0.7
26	TF-21 × TF-2 (S × S)	96	3.0	0.6
27	TF-21 × TF-5 (S × T)	96	5.3	0.6
28	TF-21 × TF-6 (S × T)	92	3.2	0.4
29	TF-21 × TF-10 (S × T)	63	3.2	0.5
30	TF-21 × TF-15 (S × S)	96	4.6	1.3
TF-5	(T)	−	6.9	1.0
TF-6	(T)	−	4.0	1.3
TF-10	(T)	−	4.6	1.2
TF-2	(S)	−	4.1	0.7
TF-15	(S)	−	5.7	0.8
TF-21	(S)	−	3.1	1.3
	LSD_0.05		0.87
^a S in the parentheses denotes summer stress sensitive, and T denotes summer stress tolerant. ^b Summer stress tolerance ratings were taken on a 1 to 9 scale with 1 being a completely wilted or dormant plant, and 9 being a green, fully turgid, actively growing plant. Turfgrass color, texture, and disease were not considered when evaluating summer stress responses.

Table 1.

Description of diallel crosses between three summer stress tolerant and three summer stress sensitive tall fescue genotypes and summer stress tolerance means across four replications and two years.

Maternal parent	Number of progeny	Maternal mean^ab	SD	Paternal mean^ac	Mid-parent mean^a	Pseudo F₂ mean^ab	SD
TF-5	96	6.1a	1.0	3.2	4.7	6.0a	0.8
TF-6	96	2.9cd	1.5	3.8	3.4	4.5bc	0.9
TF-10	95	3.4c	1.2	3.7	3.6	4.2bc	0.9
TF-2	96	2.9cd	1.2	3.8	3.4	4.6b	1.0
TF-15	96	4.5b	1.7	3.5	4.0	5.9a	1.0
TF-21	96	2.3d	1.2	4.0	3.1	4.0c	0.7
LSD_0.05		0.95				0.54
ANOVA of the Pseudo F₂
Source of variation		df	Pr > F
Year		1	0.0970		NS
Replication (year)		6	< 0.0001		***
Polycross		5	< 0.0001		***
Polycross × year		5	0.0703		NS
Residuals		30
^a Summer stress tolerance ratings were taken on a 1 to 9 scale with 1 being a completely wilted or dormant plant, and 9 being a green, fully turgid, actively growing plant. Turfgrass color, texture, and disease were not considered when evaluating summer stress responses. ^b Means followed by different lowercase letters indicated significant differences (p < 0.05) within the column. ^c Pollen source was considered one homogeneous entity for all crosses. Paternal means were calculated based on all clones involved in the polycross block excluding the maternal parent because of self-incompatibility.

Table 2.

Description and analysis of variance (ANOVA) table of the polycross block using three summer stress tolerant and three summer stress sensitive tall fescue genotypes. Summer stress tolerance means were averaged across four replications and two years.

Source of variation^a	df	Sum square	Mean square	F value	Pr >F
2012
Replication	3	13.9	4.62	9.60	1.180e-05	***
GCA	5	141.9	28.38	58.94	< 2.2e-16	***
SCA	15	25.4	1.69	3.51	7.064e-05	***
Reciprocal	15	5.5	0.36	0.76	0.7207	NS
Residuals	105	50.6	0.48
2013
Replication	3	14.8	4.94	4.66	0.00426	**
GCA	5	103.0	20.59	19.41	1.211e-13	***
SCA	15	25.9	1.73	1.63	0.07834	NS
Reciprocal	15	14.1	0.94	0.89	0.58211	NS
Residuals	105	111.4	1.06
^a GCA, general combining ability; SCA, specific combining ability. Significant at the 0.01 probability level. * Significant at the 0.001 probability level. NS not significant at the 0.05 probability level.

Table 3.

Analysis of variance table for the full diallel cross study.

Year	Narrow-sense heritability	Standard error
2012	0.578	0.059	***
2013	0.825	0.144	***
Combined	0.637	0.062	***
*** Significant at the 0.001 probability level.

Table 4.

Narrow-sense heritability estimates and their standard errors for summer stress tolerance ratings from the diallel study in 2012 and 2013 based on mid-parent/offspring regression.