B-I O67 July 1967 Inheritance ol Cold Tolerance, Plant Height, - Maturity and Other I Characters in u Spring- Winter Barley Cross TEXAS A&M UNIVERSITY Texas Agricultural Experiment Station R. E. Patterson, Director, College Station, Texas Summary Cold tolerance, leaf damage by low temperatures and growth habit were studied in the F1, F2 and F3 populations of a cross between l/Vill (winter) x Aim (spring) barley varieties. On a group of 85 random F2 plants and their F3 progeny families, the above cold tolerance related characters were correlated with seven agronomic and morphologic characters. Inheritance studies indicated that in this cross, growth habit and height were conditioned by three genes, maturity by two and greenbug reaction by one, with modifying factors. Correlation analysis showed that ascorbic acid content of leaves was re- lated to cold tolerance and growth habit, but the correlations were small. Survival was correlated significantly with leaf damage but not with growth habit, indicating that cold tolerance could be com- bined with more erect types. Leaf damage by low temperatures was correlated significantly with plant height and growth habit, but many exceptions were recorded. Ascorbic acid content of leaves was correlated moderately with leaf damage, leaf rust and greenbug reaction and may be worthy of further study. Neither plant height nor maturity was related closely to leaf damage, indicating , that there will be no problem of combining the types desired. Contents Summary .............................................................. ..'g Introduction ....................................................... ..; Review of Literature ........................................ .. f Materials and Methods .................................... Experimental Results ................................... .. Winterhardiness ....................................... .. i Ascorbic Acid Content of Leaves .......... ..i Growth Habit ........................................... Heading Date ........................................... Plant Height ............................................ Greenbug Reaction ................................... Interrelationship of Characters ............ Characters Related to Low Tem Reaction Entire F2 Population“; Correlation Coefficients of Grow Hardiness Factors Among 85 ' ~' Lines ........................................... .. Ascorbic Acid Content .................... Growth Habit .................................. Greenbug Reaction ........................ ..'i Leaf Rust Reaction ........................ .. Heading Date .................................. Plant Height .................................... Discussion .......................................................... Acknowledgments ............................................ ..'f Literature Cited Inheritance of Colcl Tolerance, Plant Height, Maturity and Other Characters in a Spring - Winter Barley Cross Rashad Ahmed Abo-Elenein, I. M. Atkins, E. Pawlisch, J. H. Gordenhire and K. B. Porter* WINTERHARDINESS or tolerance to 10w temperatures is a complex character which is understood poorly. Some degree of cold tolerance is important for all the barley growing areas of Texas. Selection for cold tolerance under natural conditions is difficult because of the unpredictable degree of cold to which plants may be subjected in a given location or season. Artificial freezing equipment is expensive and has been used little on barley. Ascorbic acid content of seedling leaves has been used in wheat to some extent to predict cold tolerance but has not been reported in barley. All plant breeders frequently find it desirable or necessary to use parents differing widely from the adapted cultivated type in order to obtain certain desired characteristics. In the present study, Will, the winter-type adapted variety, was greenbug re- sistant and adapted to most of the Texas barley- growing areas. Aim, the other parent, was a spring- type variety poorly adapted to Texas and lacking in cold tolerance but resistant to leaf rust and of desirable short stature. Major objectives were to combine the good characteristics of the two parents to provide a better barley for high production levels and deter- mine the manner of inheritance of characters to im- prove the efficiency of breeding methods. REVIEW OF LITERATURE Low temperature hardiness is of three types: (a) resistance to low temperatures, (b) resistance to chilling or sudden freezes and (c) resistance to frost injury. Reid (16) reported on hardiness in l3 winter x spring crosses. Varieties differed in their ability to contribute to hardiness of progeny. Kearney and Dicktoo (winter-type) contributed more hardiness in crosses than other hardy varieties tested. Minsturdi and C.I. 58901 (spring-type) contributed more to hardiness of progeny than any other spring variety. Transgressive segregation was not reported. None of the l8 crosses gave lines which averaged as hardy as the winter parent, although individual F4 lines from each cross were within the range of the hardy parent. Rhode and Pulham (17) studied hardiness in 18 barley varieties, crossed in a diallel series. The phenotypic expression of winter-hardiness varied from complete dominance of a high degree of cold tolerance to complete dominance of susceptibility to cold injury. The effect of the major genes ap- peared to be additive. They obtained high correla- ‘C. I. refers to the accession number of the Cereal Crops Research Branch, Crops Research Division, Agricultural Re- search Service, U. S. Department of Agriculture. *Respectively, former graduate student from Egypt; research agronomist, Agricultural Research Service, USDA and small grains section leader, Texas Agricultural Experiment Station; former assistant professor, Texas Agricultural Experiment Station; assistant agronomist, North Central Texas Research Station, Denton; and professor, USDA Great Plains Research Center, Bushland. tion values between leaf damage and winter survival, indicating that leaf damage notes may be valuable to the breeder eve-n when no actual differential win- terkilling occurs. High correlations also were ob- tained between artificial freezing tests and survival under natural conditions in the field. The herita- bility estimate was 85 percent when calculated from all data, but it was lower, 49 percent, when calculated from only the hardy progenies. Dantuma (6) re- ported transgressive segregation for winterhardiness. Smith (l9) cites several workers who found spring growth habit dominant and controlled by one gene. Nilan (l4) cites the work of Takahashi and others who report three genes, one recessive and two domi- nant, controlling spring habit. These were influenced also by length of day. Reid (15) studied growth habit in 59 crosses involving l2 spring and 5 winter- type varieties. On the basis of one recessive factor pair (aa) and an unrelated dominant pair (BB), either of which conditioned spring growth habit, he grouped the spring varieties into three classes aaBB, AABB and aabb. The winter varieties were all of the AAbb genotype. Several other interpreta- tions of growth habit were found in the literature. Several workers obtained winter-type segregates from crosses between spring varieties and several inter- pretations of this were found in literature. Moseman (12) found some relationship of growth habit and cold tolerance, but Schiemann (18) stated that winterhardiness is independent of the genes controlling growth habit. Futrell and Pilgrim (8) found that when plants were hardened by exposure to cold, winter-type varie- ties of wheat had higher concentrations of ascorbic acid than spring types; however, when the plants were growing rapidly, the differences between the types were not significant. Andrews and Roberts (3) reported similar results and were able to increase cold tolerance in seedlings by supplying them with an aqueous solution of ascorbic acid. Plant height has been reported as controlled by one, two or more genes. In most instances, tallness was dominant. Neatby (13) reported that four genes . govern the difference between the short “guy mayee” variety and Canadian Thorpe. The “Uzu” type has been used in attempts to obtain short, strong-strawed barleys. Barker (4) studied height inheritance in five barley crosses involving the “Uzu” type and found two or three genes for height in addition to the “Uzu” type. Tallness was dominant, and additive gene action was indicated with continuous variation from the short to tall parent plus transgressive segrega- tion for height. Most heritability estimates for height were low or medium because of the influence of environment. Maturity in barley likewise is greatly influenced by environment. Heritability values reported for ma- turity were usually high. For example, Fiuzat and Atkins (7) report values of 90 to 92 percent. They 4 report one major gene pair plus modifyingti Neatby (13) reported three pairs of genes [ turity and Barker (4) reports a minimum or four major pairs with dominance, additi’ action and epistasis apparent. In the ma <- worked with, there was a significant positive tion between height and heading dates. A Gardenhire and Chada (9) found V resistance was conditioned. by a single gene. man and Roane (12) reported that the var' was resistant to all cultures of leaf rust i possess a gene not found in other varieties. if MATERIALS AND METHODS The parent varieties used in this st =5 Aim, (C.I. 3737) and Rogers x Kearney (C.I. a strain which was later bulked with a sist. C.I. 10879 to make up the variety Will (l0 characteristics of the parents follow. ‘ CHARACTER VARIETY t Growth habit Aim, P1 0.1.1, Height Short 1 Winterhardiness Tender Maturity Early 1 e, Leaf-rust reaction Resistant S Greenbug reaction Susceptible i? . The cross of Aim x C.I. 10880 was spring of 1962. The F1 plants were gro controlled temperature greenhouse during the‘, of 1962. Data were recorded for the F1, F‘ and parents. During the 1962-63 crop F2 and parents were grown in 4-inch spaced § part at College Station and part at the USD western Great Plains Research Center, j Texas. The winter was so severe that onl? plants survived at Bushland. At College Sta Aim parent winterkilled but most plants, other populations survived. ’ The cross was remade in the spring During the 1963-64 crop season, 30 F1 parents and 385 F3 rows were space-seeded i__ rows at College Station while the parents, i varieties Goliad and Cordova, for meas‘ range cold tolerance, and 358 F3 rows at Bushland. Winter weather conditions W’ able for rating hardiness at Bushland, bu"); temperature injury occurred at College St; Data on growth habit, plant height, if survival, leaf damage ratings and leaf rust? under field conditions were taken on the and parents at College Station in 1963. Gro "1 maturity and plant height data were ta group of random F3 rows at College Statio ' Plants were classified for growth habit". type l being similar to the Will parent I; being similar to the Aim parent. An aver‘ was made of F3 rows on the same scale, t ' Survival of Will, Goliad, Cordova and Aim barley varieties at Bushland, Texas, 1964. ‘random F3 rows were classified in detail. the tallest spike of each F2 plant, parents all plants in 35 F2 rows was measured in iHeading date was recorded for the earliest each F2 plant and parent. A base date _i 1 was used for all plants and parents. i heading of the earliest and latest plant in irow were recorded. y‘ damage ratings were made February 2 on 2 at College Station after a temperature of lad occurred a few days before. The Aim a few plants of other populations were _ Damage ratings were made on. a scale of Will parent was rated 1 and the Aim i ted 6. This same freeze killed all but two ' at Bushland. During the 1963-64 season, damage occurred at College Station. The Ffnt was killed at Bushland, but the tender ‘Y oliad partially survived and Cordova was j only slightly. Differential injury among was evident; therefore, the rows were classi- icovery was such, however, that no analysis was attempted. fe readings of ascorbic acid content in each dom juvenile F2 plants and plants of the int were made at College Station on March 9.1963, when the temperature was near 45° i; Aim parent was killed before this. The gused was that of Loeffler and Pouting as by Pilgrim? nbug resistance tests were made on F2 plants 2 Denton in 1963. Since the ratio obtained rmal, the F3 families were tested in 1964. i ods and procedures were those described Leaf rust readings were made on F2 d parents growing in the field in 1963. j. The ascordic acid content of stem rust sus- I resistant wheat. PhD thesis Texas A8cM University 1955. mun —-- Statistics such as the mean, variance and tests of significance were calculated by the methods out- lined by Snedecor (21) and Steel and Torrie (22). Observed genetic ratios were compared with theoreti- cal ratios by the X2 (Chi-square) tests for goodness of fit. The inheritance of plant height was studied by the method suggested by Mather (1l.) for parti- tioning the F2 variance, using F2 data. Heritability estimates on growth habit, winterhardiness, maturity and plant height were calculated by the method of parent / progeny regressio-n as described by Smith and Kinman (20). Simple correlations and multiple regression analysis for the data were made using the methods outlined by Steel and Torrie (22) . EXPERIMENTAL RESULTS Winterhardiness The parents differed widely in cold tolerance. At College Station in 1963, Aim was killed but “Till was damaged only slightly. At Bushland in 1964, Aim was killed and Will survived. Goliad was damaged moderately, but Cordova was damaged only slightly in this test. A near normal distribu- tion for leaf damage of plants at College Station in 1963 is presented in Table 1. Twenty-five F2 plants and the Will parent were classed 1, while 20 plants and the Aim parent were winterkilled. Leaf damage ratings of F3 were obtained at Bushland in 1964, TABLE l. FREQUENCY DISTRIBUTION OF LEAF DAMAGE OF F2 PLANTS OF AIM X WILL BARLEY GROWN AT COLLEGE STATION, TEXAS, 1962-63 Classesl Population l 2 3 4 5 6 Total P1 4O 4O P2 4O 4O F2 25 63 l l5 182 27 2O 432 lScale ranges from l (no damage) to 6 (winteirkilled). TABLE 2. MEAN ASCORBIC ACID CONTENT OF LEAVES OF F2 PLANTS OF AIM X WILL BARLEYS GROUPED BY LEAF DAMAGE CLASSES, COLLEGE STATION, TEXAS, 1963 Winter- Number of Ascorbic MR2 hardiness samples acid content class (Mgsll 1 so 81.22 I 2 27 76.52 3 51 . 65.83 4 12o 61.36 l 5 15 45.57 | ‘Milligrams of ascorbic acid per 100 grams of fresh leaf tissue. zMultiple range—means not connected by the same line are sig- nificantly different at the 5% level. and heritability of F2 with F3 was calculated to be 85 percent. Ascorbic Acid Content of Leaves The ascorbic acid content of seedling leaves by winterhardiness classes 1-5 is given in Table 2. Multi- ple range tests of these classes show that hardy, inter- mediate and tender classes differed significantly in ascorbic acid content, suggesting that this test could be used to roughly classify early generation plants for hardiness. Growth Habit Growth habit distribution of F2 plants and par- ents in 1963 and of the F1 grown in 1964 are given in Table 3. The parents are distinctly different; the F1 is approximately intermediate. The F2 plants were classified throughout the range but with a large majority similar to that of the Aim parent. The F2 and F3 distributions conform to a three gene hypo- thesis, and the gene action appears to be additive and cumulative. No transgressive segregation was found. Heritability for growth habit was 40 percent. These results differ from those of Reid (15) who found growth habit controlled by one recessive pair and an unrelated dominant pair. Takahashi (23) reported three major pairs of genes, one recessive and two dominant. He found that the effect of the three major genes was not cumulative, and epistasis and incomplete dominance were reported. Heading Date The frequency distributions for days to heading of the parents in 1963 and 1964, the F2 grown in TABLE 3. DISTRIBUTION OF GROWTH HABIT OF THE PARENTS, F1 AND F2 POPULATION OF AIM X WILL BARLEYS GROWN AT COLLEGE STATION, TEXAS, 1963-64 Population and Growth habit‘ year grown 1 2 3 4 5 6 7 . Total Aim, 1963, 1964 40 40 Will, I963, 1964 40 40 F1 1964 23 4 27 F2 1963 8 11 11 40 17 35 314 436 ‘Scale ranges from 1 = (winter-type) to 7 (spring-type). 6 1110- 90- aQ-i 70-' F2, was a w- i! E 3 U’ g so- IL 4o- wt: 2°‘ P2 (c.1. 1osao),1 - I r (c.1- 1,11 l: (A11), 1964 H. m‘ \ 1 t ¢P*~ --—-~ ,~"- ‘g \ —" _-.“:::::--' ‘\ ~—--» ~ * a I I I I I I I I I I r I 14 l6 l8 20 22 24 Z6 28 30 32 34 36 38 Days to Heading ~ Figure 2. Frequency distribution for days to h,‘ P1, P2, F1 and F2 plants of the cross Aim x C.I. 10880.‘ College Station, Texas. ‘Y 1963 and the F1 grown in 1964 are shown iri 2. No data for the Aim parent are available 1 because it was winterkilled. The means of = ents, F1 and F2 were shown by Duncan's range test to be significantly different. mean of the F1 and F2 are to the left of p“ parent value. Partial dominance of early if] is indicated in this cross, and transgressive sei beyond the late parent Will was observed F2 grown in 1963. It is suggested that at major factors, and perhaps modifying fac v operating in this cross, which agrees with of other workers. Heritability for matu relatively low —— only 34 percent. 1 Plant Height The tall parent Will ranged from 29 t0 while Aim measured 13 to 21 inches. The l‘ from 11 inches to plants equally as tall as I plants of Will. Distribution is shown in i; and some of the F2 and parent plants are. Figure 4. Both dominant and additive gen‘ were indicated. Dominance, heritability, r effective factors and possible selective ad given in Table 4. The low heritability". is expected in cases where a number of ;' TABLE 4. DOMINANCE, HERITABILITY, NUMBER OF “P; TORS K1 AND K2 AND POSSIBLE SELECTIVE ADVANCE. HEIGHT IN THE WILL X AIM CROSS ‘I Estimatedi. Statistics lH/D) v, 3-9 lover-i‘ Heritability 9%‘ 1. Effective factors K1 3.70 K2 6.02 lKgDl I/z 3.75 VFz ‘Calculated as X 100. 1/ D 2 :_‘ zCalculated by the parent/progeny regression method i, by Smith and Kinman (20). » e difference between the two estimates _ of effective factor pairs could be due unequal gene effects 0r non-iso-directional i n 0f allelomorphs. The immediate selec- found to be i- 3.8 inches from the I value of 35.0 inches. Since the parents ‘A their mid-value by 2.9 inches, it appears “t any plant markedly transgre-ssing the l be selected. The shortest F3 mean of ‘lured was 33.0 inches and the tallest was departures of 4.6 and 2.0 from the mid- e. As only 85 F3 families were measured, __fflbable that any with all the height genes ‘ggrecovered in this number. Greenbug Reaction ifrom six F1 plants were used to test separ- greenbug reaction of F2 families. Five populations gave ratios of three resistant fps-one susceptible, in agreement with work iand Gardenhire (9). In one family, there lbnormally high population of susceptible Ijthat the ratio was abnormal. Two other f? so had somewhat abnormally high propor- iusceptible plants so that Chi-square values erline. The total for all six families gave f} to 547 susceptible which also deviates if» from a 3:1 ratio with a Chi-square value fid a P value of 0.025-0.01. 2 ‘e 0f the variability of F2 results and varia- no data on greenbug tests obtained by other i F2 P2 (C.I. 10880) i: P1 (Aim) l1...----*'\——-‘ Height in inches xas, 1963. '1 5 Frequently distribution of plant height for P], P2 '_ ts of thefcross Aim x C.I. 10880 grown at College aiitaaaii-‘iigtifitiiitaitititéiéi Figure 4. Will, left, and Aim, right, parents with selected Will x Aim F2 plants representing the height range of the parents. workers, seed from the 352 F2 plants grown at Col- lege in 1963 were tested as F3 lines in 1964. Results did not fit well either the 112:1 ratio or a 8:1 ratio. The observed reaction was 152 resistant: 148 segre- gating: 52 susceptible whereas the expected was 88: l76:88. The Chi-square value was 61.4. The F3 popu- lation tested was not completely random as some F2 plants were killed by low" temperature and some by yellow dwarf virus. No completely adequate ex- planation of the behavior of these populations is known, unless there are unknown modifying factors for greenbug reaction. lnterrelationship of Characters Simple and partial correlation coefficients were determined for survival, leaf damage and growth habit in 1963, Table 5. More complete comparisons were made, using the 85 strains on which ascorbic TABLE 5. SIMPLE AND PARTIAL CORRELATION COEFFICIENTS FOR SURVIVAL, LEAF DAMAGE AND GROWTH HABIT IN THE F2 POPULA- TION OF AIM X WILL, COLLEGE STATION, TEXAS, I963 r Partial r 2. 3 2 3 I Survival —0.34** —0.06 O.49** 0.25 2 Leaf damage O.62** 3 Growth habit “Significant at the I % level. TABLE b. SIMPLE CORRELATION COEFFICIENTS AMONG 11 CHARACTERS IN THE CROSS OF WILL X AIM BARLEYS Simple correlation coefficients Character 2 3 4 5 Leaf damage in F2 .69** -—.4é** .84** .61** Leaf damage in F3 —.28* .69** .49** Ascorbic acid in F2 -—.41** -—.19 Growth habit in F2 .72** Growth habit in F3 Plant height in F2 Plant height in F3 Heading date in F2 Heading date in F3 .Leaf rust in F2 Greenbug reaction in F3 —'_O~ooo\1o~mz-wro- a 7 s 9 1o ~.3<>** ~.17 ~.70** .as** ~.2a* -.s4** -.1a -.a1** -.sa** -.22 :_' .35** -.12 .43** .42** .44**; -.29* +22 -.sa** -.7a** ~.37**; -.24 -.24 -.73**_ j1-.