Further evidence of polygenic inheritance of partial resistance in barley to leaf rust,Puccinia hordei

Summary The latent period (LP) is a crucial component of partial resistance. Five cultivars, L94, Sultan (Su), Volla (Vl), Julia (Ju) and Vada (Va), representing the known range in partial resistance and LP were crossed in a diallel, and the F₁, F₂ and F₃ tested. The LP effectuated by the five cultivars is about 9, 10^1/2, 10^1/2, 13 and 15^1/2 days, respectively. The crosses Su×L94, Vl×L94 and Ju×L94 had an F₂ positively skewed. Their F₂ means were similar or only slightly larger than the F₁ means. The F₂ frequency distributions in the crosses Vl×Su, Ju×Su and Ju×Vl were normal or nearly so with F₁ and F₂ means similar to each other and to the mid-parent value. The crosses involving Va as a parent again showed a positive skewness but with F₂ means considerably larger than the F₁ moans.Most F₂'s ranged from the low parent to the high parent values without transgression. In the crosses Va×L94 (reported earlier) and Ju×L94 the parental values were not recovered among 216 and 154 F₂ plants, respectively. The cross Ju×Va showed transgression beyond the low parent, Ju.From these data it is concluded, assuming no linkage, that seven loci are involved. The + alleles (governing a longer LP) are thought to be distributed over the parents as follows: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGceaqabeaacaqGmb% GaaeyoaiaabsdacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaab2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGTaGaaeylaiaabccacaqGGaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeylaiaab2caca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaa% b2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae% iiaiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGaGaaeiiaiaabc% cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGTaGaaeyl% aiaabccaaeaacaqGtbGaaeyDaiaabccacaqGGaGaaeiiaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaa% bccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae% 4kaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqG% RaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2% cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeii% aiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccacaqGGa% GaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGTaGaaeylaa% qaaiaabAfacaqGSbGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGaaeiiaiaabc% cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGaaeii% aiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGa% GaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUca% caqGRaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiai% aab2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGa% aeiiaiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2cacaqGTaaabaGaaeOs% aiaabwhacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGa% GaaeiiaiaabccacaqGGaGaae4kaiaabUcacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaabccacaqGGaGaae4kaiaabUcacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaabccacaqGGaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaa% bccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2cacaqGTaGaae% iiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeylaiaab2caaeaacaqGwbGaaeyyaiaabccacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcaca% qGRaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae4kaiaa% bUcacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae% 4kaiaabUcacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeylaiaab2cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabc% cacaqGGaGaae4kaiaabUcacaqGGaGaaeiiaiaabccacaqGGaGaaeii% aiaabccacaqGGaGaaeiiaiaabUcacaqGRaaaaaa!1BBA!\[\begin{gathered} {\text{L94 - - - - - - - - - - - - - - }} \hfill \\ {\text{Su + + + + + + - - - - - - - - }} \hfill \\ {\text{Vl + + + + - - + + - - - - - - }} \hfill \\ {\text{Ju + + + + + + + + + + - - - - }} \hfill \\ {\text{Va + + + + + + + + - - + + + + }} \hfill \\ \end{gathered} \]The genes are supposed to act additively (intermediate inheritance) with the exception of one locus (the 6th or 7th locus) which shows dominance for the shorter LP (for the-alleles). The effect of this locus on LP seems considerably larger than that of the other loci. There are indications of physiological barriers, which means that LP's shorter than the one of L94 or much longer than that of Va are not possible.The effect of + genes in genotypes governing LP's close to these barriers (with very few or very many + alleles respectively) is smaller than in genotypes governing intermediate LP's.     

Inheritance of resistance to pea blight (Ascochyta pinodella) and induction of resistance in pea (Pisum sativum L.)

Summary Pea blight caused by Assochyta pinodella does considerable damage to the pea crop every year. To ascertain the inheritance of resistance to pea blight and incorporate resistance in the commercial cultivars, crosses were made between Kinnauri resistant to pea blight and four highly susceptible commercial pea cultivars — Bonneville, Lincoln, GC 141 and Sel. 18. Studies of the F₁'s, F₂'s, back crosses and F₃'s indicated that Kinnauri carries a dominant gene imparting resistance to pea blight.     

Inheritance of resistance to black rot (Xanthomonas campestris pv. Campestris) in cauliflower (Brassica oleracea var. Botrytis)

Summary Black rot disease caused by Xanthomonas campestris pv. campestris is a limiting factor in the commercial production of the cauliflower crop. Crosses were attempted between SN 445, a mid season cultivar resistant to black rot and two highly susceptible commercial cultivars (Pusa Snowball-1 and K-1). Studies of the F₁'s, F₂'s and back crosses indicated that SN 445, carries a dominant gene imparting resistance to black rot.     

Inheritance of resistance to Fusarium wilt in Indian lentil germplasm (Lens culinaris Medik.)

Summary Three lentil genotypes resistant to Fusarium oxysporum f.sp. lentis viz. Pant L 234, JL 446 and LP 286 were crossed with two susceptible ones. The hybrid plants were all resistant in the eight crosses evaluated. Segregation pattern for wilt reaction in F₂, BC(P₁), BC(P₂) and F₃ generations in field and glasshouse conditions indicated that resistance to Fusarium wilt is under the control of two dominant duplicate genes in Pant L 234 and two independent dominant genes with complementary effects in JL 446 and LP 286. A third dominant gene complementary to the dominant genes in JL 446 and LP 286 is present in two susceptible lines. Allelic tests suggest the presence of five independently segregating genes for resistance. Duplicate dominant genes in Pant L 234 are non-allelic to two dominant genes with complementary effects in LP 286 and JL 446 and the third gene complementary to the two genes in JL 446 and LP 286 in susceptible lines JL 641 and L 9–12. Gene symbols among parental genotypes have been designated.     

Inheritance of resistance to potato virus Y in garden pepper (Capsicum annuum L.)

Summary Bell pepper suffers considerable losses from a strain of potato virus Y (PVY^o-sbp). Crosses were attempted between two resistant lines Perennial and S41-1 and two highly susceptible bell pepper commercial cultivars California Wonder and Yolo Wonder. Studies of F₁'s, F₂'s, back crosses and F₃'s indicated that Perennial and S41-1 carry a recessive gene imparting resistance to potato virus Y.     

The inheritance of nitrate content in lettuce (Lactuca sativa L.)

Summary The inheritance of nitrate content in lettuce was analysed using 16 F₂ populations and three F₃ populations. Frequency distributions of nitrate content in F₂ and F₃ populations were unimodal and symmetrical, indicating a quantitative inheritance. Both significant positive and negative deviations of the F₂ mean from the mid-parent value were found, indicating dominance or epistasis. Deviations towards low nitrate content were more frequent than deviations in the other direction. Estimates of heritabilities for nitrate content in the F₂ populations ranged from 18% to 69% and were in most cases above 50%. Crosses between low nitrate cultivars did not have lower estimates of heritability in the F₂ than crosses between cultivars with larger differences in nitrate content. In one case a genotype x experiment interaction for nitrate content of parental cultivars was found.Three F₃ populations of crosses between cultivars with low nitrate content were analysed. Estimates of heritabilities for F₃ line means ranged from 78% to 91% and estimates of the genetic standard deviation of nitrate content in unselected advanced generations ranged from 0.24–0.33 g kg^–1. The estimates of heritabilities and of genetic variation in advanced generations offer good prospects of selection of low nitrate genotypes in lettuce. A comparison of efficiency of selection in the F₂ generation and F₃ line selection is made.     

Inheritance of resistance to angular leaf spot in Nicotiana tabacum L. cultivars burley 21 and kentucky 14

Summary The genetics of resistance to angular leaf spot caused by Pseudomonas syringae pv. tabaci in Nicotiana tabacum cultivars Burley 21 and Kentucky 14 was investigated by studying disease reactions to three isolates of parental, F₁, F₂ and backcross generations derived from crosses between the resistant cultivars and the susceptible cultivar Judy's Pride. Studies were conducted in the greenhouse and in field plant beds. Chi-square values were computed to determine whether the observed ratios for disease reactions deviated from expected Mendelian ratios for a single, dominant gene controlling resistance to angular leaf spot in tobacco. Based on the resistance of the F₁ and the backcross generation to the resistant parent (BC-R), a 3 resistant: 1 susceptible segregation ratio in the F₂, and a 1 resistant: 1 susceptible segregation ratio in the backcross generation to the susceptible parent (BC-S), it was concluded that resistance to three isolates of Pseudomonas syringae pv. tabaci is governed by a single, dominant gene.     

Inheritance of resistance to fruit rot (Phytophthora parasiticaDast.) in tomato (Lycopersicon esculentum Mill.)

Summary Fruit rot disease caused by Phytophthora parasiticaDast. is a limiting factor in tomato production in Himachal Pradesh. 30 to 60 per cent fruits are damaged by this disease. Crosses were made between EC 54725 (Lycopersicon pimpinellifolium), a small tyuited type, resistant to fruit rot and four highly susceptible tomato commercial cultivars (Gola, Sioux, S12, and Lalmani). Studies of F₁'s, F₂'s and back crosses indicated that EC 54725 carries a dominant gene imparting resistance to fruit rot.     

Inter-and intraracial hybridization and selection for seed yield in early generations of common bean,Phaseolus vulgaris L.

Summary Five parents from each of four race groups of common bean (Phaseolus vulgaris L.) were hybridized to produce five crosses within each group. Also, five crosses were made for each of the six possible combinations among four groups. Parents, F₁ and F₂, and parents, F₂ and F₃ were evaluated for seed yield in 1990 and 1991, respecitively, at two locations in Colombia.Yield of parents belonging to Middle American races and crosses among them was higher than that of races of Andean origin. Positive correlations were found among the mid-parent value, F₁, F₂ and F₃. Also, the mid-parent value predicted the mean seed yield of all possible lines that could be derived from the F-generation in 42 out of 47 crosses. Four crosses, all between common bean races of Andean and Middle American origin, indicated a possible loss of favorable epistatic parental alleles. On average, mean yield of interracial F₁ hybrids was higher than that of intraracial ones.Positive heteroris (26.4%–123.8%) over the mid-parent in 31 crosses, and F₁s yielding higher (23.7%–91.8%) than the high parent in 20 crosses and yielding higher (22.1%–53.2%) than the highest control among all parents (MAM 13) in 12 crosses, were found. Heritability, estimated by the parent-offspring regression, ranged from 0.42± 0.07 to 0.49±0.04. Expected and realized gains from selection (at 20% selection pressure) ranged from 10.3% to 21.0% over the mean of F₁ hybrids and F₂ and F₃ population bulks.     

Genetics of resistance to Aphis craccivora in cowpea

Summary Inheritance of aphid resistance and allelic relationships among sources of resistance was studied in the parents, F₁, F₂, F₃, and backcross populations of cowpea crosses. Each 4-day old seedling was infested with five fourthinstar aphids. Seedling reaction was recorded 14–16 days after infestation when the susceptible check was killed. The segregation data from eight crosses between resistant and susceptible cowpea cultivars indicated that aphid resistance was inherited as a monogenic dominant trait. Segregation data from crosses among eight resistant cultivars indicated that one or two loci and modifier(s) were involved in the expression of resistance to aphids. It was suggested that further studies on allelism among sources of resistance needed to be conducted in order to resolve this.     

Inheritance of tomato leaf curl virus resistance in Lycopersicon hirsutum f. glabratum

Summary Inheritance of resistance to tomato leaf curl virus (TLCV) was studied in the progenies derived from interspecific crosses between TLCV resistant Lycopersicon hirsutum f. glabratum line B 6013 and five susceptible cultivars (HS 101, HS 102, HS 110, Pusa Ruby and Punjab Chhuhara) of L. esculentum. P₁, P₂, F₁, F₂, B₁ and B₂ progenies of the five crosses were artificially inoculated with local strains of TLCV by means of the vector whitefly, Bemisia tabaci (Genn.). and the disease reaction was studied in all the crosses. Reaction of parents, F₁, F₂ and backcrosses suggests that resistance derived from L. hirsutum f. glabratum B 6013 is based on two epistatic genes, one from the wild parent and one from the cultivated one, resulting in a 13:3 segragation in the F₂.     

Genetics of disease resistance in urdbean (Vigna mungo (L.) Hepper) to the leaf spots caused by Colletotrichum truncatum (Schw.) Andrus & Moore

Summary The resistance sources among various test cultivars of urdbean to Colletotrichum truncatum, a leaf spotting pathogen, were identified and genetics of resistance was worked out by studying F₁, F₂ and F₃ generations of crosses between resistant cultivars and the susceptible cv. Kulu 4 and of those among the resistant parents. The resistance was found to be controlled by single dominant genes and the resistance genes were non-allelic.     

Resistance of lettuce (Lactuca) to the leaf aphid Nasonovia ribis nigri. 2. Inheritance of the resistance

Summary The inheritance of resistance to Nasonovia ribis nigri in L. sativa was investigated. Parents and F₁ and F₂ populations from crosses between the susceptible cultivar Ravel and two resistant breeding lines were tested. In both breeding lines one dominant gene appeared responsible for resistance.     

Heterosis and inbreeding depression in forage rape (Brassica napus L.)

Summary Heterosis and inbreeding depression for total fresh and dry weights were studied over two seasons in 15 crosses of six cultivars of forage rape (Brassica napus L.). Some of the hybrids exhibited considerable heterosis over both mid-parent and better parent; followed by depression in the F₂. The cross Windal × Canard had 62% and 25% greater dry matter yield over the best cultivar used in this experiment in 1978 and 1979, respectively. Possibilities of the utilization of this hybrid superiority are discussed.     

Inheritance of groat protein percentage in Avena sativa L. × A. Fatua L. Crosses

Summary Gene action and heritability of groat protein percentage were determined in F₁, F₂, and F₃ generations of nine crosses between three Avena sativa L. cultivars and three A. fatua L. selections. Relationships among groat protein percentage, grain yield, and 100-seed weight also were evaluated. The three A. sativa parents were Dal (high grain yield and intermediate groat protein percentage), Goodland (low grain yield and high groat protein percentage), and Stout (high grain yield and low groat protein percentage). The three A. fatua parents were chosen for the study on the basis of vigorous plant growth and high groat protein percentage. The study was conducted at Madison, Wisconsin in 1979 and 1980.There was partial dominance towards low groat protein percentage. Narrow sense heritability estimates for groat protein percentage were low in Dal and Goodland crosses and intermediate in Stout crosses. In the F₂ generation, groat protein percentage was significantly higher in shattering than in nonshattering plants in 1979, but not in 1980. There were significant, positive correlations between groat protein percentage, 100-seed weight, and grain yield in F₁ and F₂ generations, but they were not large numerically. Relationships among these traits were either negative or nonsignificant in the F₃ generation. Although our results indicated that selection for higher groat protein percentage is possible when a low protein A. sativa cultivar is used, most of our simple cross progenies from A. sativa x A. fatua crosses had weak straw and were susceptible to crown rust (Puccinia coronata Cda. var. avenae Fraser and Led.).     

Variation of harvest index in several wheat crosses

Summary Harvest index was studied in F₁ and F₂ generations of eight wheat (Triticum aestivum L.) crosses and their reciprocals. The parental varieties involved in the crosses represented a fairly wide range of character expression for plant height, tillering potential, grain yield per plant and harvest index. Differences between reciprocal crosses were not evident for the expression of harvest index of the crosses under study. Means and degrees of dominance of F₁ and F₂ populations suggested partial dominance of high harvest index over low harvest index. The pattern of variation among F₂ segregates was quantitative and the distribution was normal. The gene action governing the expression of harvest index was largely additive. Evidence was obtained for non-additive gene action in some crosses. There was complete absence of high parent heterosis for harvest index in the F₁'s but midparent heterosis was found to be present in all crosses. Estimates of heritability and genetic advance were moderate to high. Usefulness of selecting for harvest index as a measure of yield efficiency particularly in early generations is discussed.     

Response to selection in F2 generations of winter wheat for resistance to head blight caused by Fusarium culmorum

Summary In a field trial, F₃ winter wheat lines from plants selected for Fusarium head blight resistance in F₂ generations of a set of crosses, composing a 10×10 half diallel, were tested with their parental lines for resistance to Fusarium culmorum. Selection responses averaged 3.7% on the head blight percentage scale and ranged from –22.0% to 27.1%. Realized heritabilities averaged 0.23 and ranged from 0 to 0.96. Significant transgression for resistance was observed which was suggested to be genetically fixed. It was estimated that resistant parents differed in one or two resistance genes. The possibility of accumulation of resistance genes was shown. The level of head blight resistance of the parental line appeared to be a good indicator of the potential resistance level of its crosses.     

Variation in pigment content of flour color in bread wheat (Triticum aestivum L.)

Summary Variation in pigment content of the flour of bread wheats (Triticum aestivum L.) was studied in the progenies of F₁ and F₂ of three crosses and their reciprocals. Reciprocal differences in pigment content were observed in the F₁ and F₂ means. Low pigment content was found to be partially dominant or over dominant in the crosses studied. There was evidence of substantial mid-parent F₁ heterosis in all crosses and betterparent F₁ heterosis in three crosses. In the F₂, heritability estimates were moderate to high. The F₂ frequency distributions were not normal. Estimation of effective factor pairs indicated the presence of one or two major gene pairs involved in the expression of pigment content in the flour. Action of modifiers was also assumed in one cross and its reciprocal. A factorial approach to metrical character suggested that the F₂ segregation ratios of low pigment content to high pigment content were 3:1, 15:1, 13:3 and 9:7 for the different crosses. Utilization of the findings in a wheat breeding program is briefly discussed.     

Inheritance of reaction to Pseudomonas lachrymans in pickling cucumber

Summary Cucumber (Cucumis sativus) lines resistant to angular leafspot caused by Pseudomonas lachrymans react to an infection by developing necrotic lesions that lack the chlorotic halo characteristic of the susceptible reaction. The inheritance of the non-halo lesion reaction was studied in all possible crosses between resistant lines MSU 9402 and Gy 14A, and susceptible cultivars Wisc. SMR 18 and National Pickling. Genetic analysis of the F₁, F₂, backcross and F₃ populations revealed that the non-halo lesion type, associated with resistance, was controlled by a single recessive gene, pl. This character appears to be an important component of resistance to P. lachrymans.     

Inheritance of resistance to fruit rot (Phytophthora capsici Leon.) and induction of resistance in bell pepper (Capsicum annuum L.)

Summary Fruit rot in bell pepper caused by Phytopthora capsici Leon. is a limiting factor in its commercial production. Crosses were made between Waxy Globe, a small fruited hot type, resistant to fruit rot and four highly susceptible bell pepper commercial cultivars (Chinese Giant, California Wonder, Osh, Kosh and Yolo Wonder). Studies of the F₁'s, F₂'s and backcrosses indicated that Waxy Globe carries a dominant gene imparting resistance to fruit rot. After three backcrosses with California Wonder, lines were obtained combining the resistance gene of Waxy Globe with the large fruit size and low capsaicin of California Wonder.