الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 144 |  |  |
| | | from | 144 | | |
Abstract
The research focused on objective evaluation of certain genotypes of cowpea and the production of high-quality cowpea crosses. The present study aims, via its crossings with introduced cultivars, such as Colossus cv and Asian introduction, to improve the qualities of local commercial cultivars, such as Cream 7, Dokki 331, and Commercial 1. Meanwhile, two experiments were conducted, the first experiment evaluates the morphological, floral, pod, and seed characteristics, as well as yield, of five distinct cowpea genotypes: local commercial cultivars, Cream 7, Dokki 331, and introduced genotypes, Colossus cv. and Asian introduction. In addition to Commercial 1 cv., which was gathered from local markets owing to the high quality of its seeds as well as consumer attractiveness.
On the other hand, the results of the 2nd evaluate the morphological, floral, pod, and seed properties, as well as yield, of six different cowpea crosses from two generations apart; F1 and F2. Local commercial cultivars Cream 7, Dokki 331, and Commercial 1, as well as imported genotypes Colossus cv. and Asian introduction, were used as parental materials in this experiment. The parental genotypes and their six F1s and F2s were studied over the seasons of 2018, 2019, and 2020. In the summer of 2018, six F1 crosses were produced from these five genotypes. F1 seeds were sown as previously specified in order to produce F2 plants the following season. Both field experiments were carried out, and all genotypes/crosses were grown for three succulent seasons under the conditions of the El-Minia governorate.
The obtained results of these experimental studies are summarized as follows:
Evaluation of parental genotypes
- The result showed that there were significant differences in shoot length, no. of branches/plant, pre-leaf length and width, no. of peduncles/plant, pod length, peduncle diameter, no. of aborted ovules/pod, pod weight, seed width, dry pod weight/plant and the weight of seeds/plant among the examined parental genotypes, i.e., Cream 7, Dokki 331, and Commercial 1, Colossus cv. and Asian introduction.
- Dokki 331cv. had the highest number of branches/plants in the first season, the longest mean peduncle length in the first and second seasons and the highest number of pods/plants in the second season. On the other hand, Dokki 331 cv., had the smallest value of seeds per pod in all seasons. Dokki 331, had a poor dry pod yield, which was evident in the first and third seasons.
- Cream 7 cv. gave the highest values of the no. of branches/plant in the 2nd and 3rd seasons, also Cream 7 had the highest stem diameter and no. of pods/plants value in the 1st and 3rd seasons. On the other hand, Cream 7 cv. a local commercial cultivar produced the lightest seeds weight/pod.
- Commercial 1 cv. had the maximum leaflet length and width and was the best genotype and produced the longest pods. Also, Commercial 1 cv. had the maximum average pod weight. Commercial 1 cv., and Colossus cv., an introduced cultivar, produced the heaviest seeds weight/pod.
- Colossus cv. and Commercial 1 cv. produced the highest leaflet length and width. Also, Colossus cv. ranked after Commercial 1 cv. in the
average pod weight. According to statistical analysis of the assessed genotypes, Colossus cv. has the largest seed width values. Colossus cv. outperformed the others in terms of dry pods weight per plant and weight of seeds per plant.
- Asian introduction had the longest mean shoot length and flower length while tracked the smallest leaflet width. Asian introduction and Commercial 1 cv. were the best genotypes and produced the longest pods while Asian introduction recorded the minimum value in 1st season. Also, Asian introduction produced the highest mean number of seeds per pod in all seasons. It displayed the longest average seed length in the three growing seasons.
Evaluation of the crosses of F1 and F2 generations
- The extent of variability present in cowpea cultivars was measured in terms of genetic parameters viz., genotypic and phenotypic coefficients of variation, heritability, and genetic advance mean of different traits.
- The F1 of Dokki 331 x Asian introduction cross produced the tallest shoot and longest pod length, also F2 of the crossing between Colossus and Asian introduction generated the longest pod length.
- Colossus x Commercial 1 cross had more peduncle diameter and generated the most seeds per pod, and recorded the highest leaf length for F1 and F2.
- The F1 and F2 of the cross Cream 7 x commercial 1 was superior to the other crosses, which had a taller peduncle than better-parent, and produced the most peduncle and the tallest pre-leaf.
- F1 of Colossus x Commercial 1 cross and F2 of Cream 7 x Asian introduction cross produced the highest values of branches\ plant, also.
For flower length, none of the tested crosses exhibited higher values than the better genotype Asian introduction.
- The F2 Cross Colossus x Commercial 1 had the greatest results and had the fewest aborted ovules per pod, also for seeds weight/pod, the cross Colossus x Commercial 1 cross was superior in the two generations but still weighed less than the better parents Commercial 1 (2.7 g) and Colossus (2.6 g).
- The F1 of the cross Dokki 331 x Asian introduction had the greatest value and outperformed the parental genotypes for seeds weight per plant as well as the other crosses in F1. Also, the same cross outperformed the better parent, Cream 7 cv. in terms of pods/plants.
- Cream 7 x Asian introduction cross had the best dry pod weights however it is still less than the better parent.
Genetic parameters estimation
- This study showed that there is sufficient genetic variance to warrant selection for improvement in the cowpea crosses.
- Heritability (h) estimations for shoot length were high for crosses in the first generation, with the exception of the F1 Dokki 331 x Asian introduction cross, which had a lower heritability value (50 %). Genotypes had high heritability values for number of branches/plant except for the Asian introduction. High levels of the genetic advance mean (GAM) were attained for all parents and crosses in terms of the number of branches per plant.
- For leaflet length, the best results PCV %, GCV %, h %, and GAM were produced by F1 of the cross Colossus x Asian introduction, followed by F1 of the cross Cream 7 x Asian introduction. In regard to leaflet width, cross
Cream 7 x Commercial 1 demonstrated high scores of the estimated genetic traits of leaflet width.
- Values for peduncle length varied for the calculated parameter. PCV %, GCV % for parents in three seasons, and all parents assigned a high value to h % for peduncle length and number of peduncles/plant.
- In F1 and F2, the phenotypic variance was greater than the genotypic variance in the five parents and the six crossings for the number of pods per plant. Parental genotypes and crossings of F1s and F2s had also high heritability values for pod length.
-The heritability % and GAM of the no of seeds/pod were high in all parents and the resultant crosses in F1 and F2. Five parents had high values for the PCV %, GCV %, h %, and GAM of the no. of aborted ovules per pod. All crosses in F1 and F2 recorded high values for h % except for F1 of the crosses, Dokki 331 x Commercial 1 and Cream 7 x Asian introduction which had moderate values for h% for pod weight. On the other hand, F1 and F2 crossings yielded moderate and high PCV and GCV % of seeds weight/pod values.
- According to genetic analysis, the tested five parents in three seasons achieved high levels for h % and GAM of dry pods weight/plant and the produced six F1 and F2 crosses exhibited a high heritability % and genetic advance in terms of dry pods weight/plant, while higher PCV values than GCV were reported for seed weight per plant of five parents and six crossings in F1 and F2.
- Based on the data and the cowpea breeding program’s goal of producing more productive, upright, and early genotypes, crossings between the genotypes Cream 7 x Commercial 1 and Dokki 331 x Asian introduction were selected as the most promising for achieving increases in these characteristics.