A toolkit to rapidly modify root systems through single plant selection

Background The incorporation of root traits into elite germplasm is typically a slow process. Thus, innovative approaches are required to accelerate research and pre-breeding programs targeting root traits to improve yield stability in different environments and soil types. Marker-assisted selection (MAS) can help to speed up the process by selecting key genes or quantitative trait loci (QTL) associated with root traits. However, this approach is limited due to the complex genetic control of root traits and the limited number of well-characterised large effect QTL. Coupling MAS with phenotyping could increase the reliability of selection. Here we present a useful framework to rapidly modify root traits in elite germplasm. In this wheat exemplar, a single plant selection (SPS) approach combined three main elements: phenotypic selection (in this case for seminal root angle); MAS using KASP markers (targeting a root biomass QTL); and speed breeding to accelerate each cycle. Results To develop a SPS approach that integrates non-destructive screening for seminal root angle and root biomass, two initial experiments were conducted. Firstly, we demonstrated that transplanting wheat seedlings from clear pots (for seminal root angle assessment) into sand pots (for root biomass assessment) did not impact the ability to differentiate genotypes with high and low root biomass. Secondly, we demonstrated that visual scores for root biomass were correlated with root dry weight (r = 0.72), indicating that single plants could be evaluated for root biomass in a non-destructive manner. To highlight the potential of the approach, we applied SPS in a backcrossing program which integrated MAS and speed breeding for the purpose of rapidly modifying the root system of elite bread wheat line Borlaug100. Bi-directional selection for root angle in segregating generations successfully shifted the mean root angle by 30° in the subsequent generation (P ≤ 0.05). Within 18 months, BC2F4:F5 introgression lines were developed that displayed a full range of root configurations, while retaining similar above-ground traits to the recurrent parent. Notably, the seminal root angle displayed by introgression lines varied more than 30° compared to the recurrent parent, resulting in lines with both narrow and wide root angles, and high and low root biomass phenotypes. Conclusion The SPS approach enables researchers and plant breeders to rapidly manipulate root traits of future crop varieties, which could help improve productivity in the face of increasing environmental fluctuations. The newly developed elite wheat lines with modified root traits provide valuable materials to study the value of different root systems to support yield in different environments and soil types.

Genetic Variation of a Lentil (Lens culinaris) Landrace during Three Generations of Breeding

Genetic differentiation between 40 lentil genotypes was tested using molecular markers. The genotypes were produced from a Greek landrace of commercial interest via the honeycomb breeding methodology, i.e., single-plant selection in the absence of competition, across three successive pedigree generations. The selected genotypes from each generation were examined for genetic relationships using 15 SSR molecular markers with HRM analysis. As expected, low variation among consecutive generations at the level of 2.5–7.7% was detected. Analysis of molecular variance (AMOVA) revealed that partitioning of this variation was at higher percentage within each generation’s population than between them. Population structure analysis indicated that ongoing selection could effectively shift the allelic composition in each generation. The applied honeycomb breeding methodology that effectively improved progeny yield and seed quality increased the percentage of favorable alleles altering allelic composition but not eliminating genetic variation of the breeding population.

​Studies on Heterotic Trends in Blackgram [Vigna mungo (L.) Hepper] for Yield and Earliness

Background: As blackgram cultivation is majorly spread in rain fed areas, breeding short duration and high yielding blackgram varieties is of profound importance to tackle terminal moisture stress and reap impressive yields by breaking the yield plateau. Hence, the present study was aimed to identify highly heterotic cross combinations for yield and earliness. Methods: Six parents along with 15 F1s were evaluated (rabi, 2019) for seed yield and its component traits along with earliness to estimate the magnitude of heterosis. Result: The cross LBG-752 × TBG-104 exhibited heterosis estimates in desirable direction for yield and earliness. The next best crosses were LBG-752 × PU-31, TU-40 × TBG-104, LBG-752 × TU-40 and IPU-2-43 × TBG-104. Because of its autogamous genetic architecture and biological constraints in large scale economic hybrid seed production, heterosis could be exploited only by isolating the early maturing and high yielding segregants followed by bi-parental or recurrent selection in early segregating generations and single plant selection in subsequent generations that would result in short duration and high yielding blackgram variety that fits well into different ecological niches.

A Toolkit to Rapidly Modify Root Systems Through Single Plant Selection

Background: The incorporation of root traits into elite germplasm is typically a slow process. Thus, innovative approaches are required to accelerate research and pre-breeding programs targeting root traits to improve yield stability in different environments and soil types. Marker-assisted selection (MAS) can help to speed up the process by selecting key genes or quantitative trait loci (QTL) associated with root traits. However, this approach is limited due to the complex genetic control of root traits and the limited number of well-characterised large effect QTL. Coupling MAS with phenotyping could increase the reliability of selection. Here we present a useful framework to rapidly modify root traits in elite germplasm. In this wheat exemplar, a single plant selection (SPS) approach combined three main elements: phenotypic selection (in this case for seminal root angle); MAS using KASP markers (targeting a root biomass QTL); and speed breeding to accelerate each cycle.Results: To develop a SPS approach that integrates non-destructive screening for seminal root angle and root biomass, two initial experiments were conducted. Firstly, we demonstrated that transplanting wheat seedlings from clear pots (for seminal root angle assessment) into sand pots (for root biomass assessment) did not impact the ability to differentiate genotypes with high and low root biomass. Secondly, we demonstrated that visual scores for root biomass were correlated with root dry weight (r = 0.73), indicating that single plants could be evaluated for root biomass in a non-destructive manner. To highlight the potential of the approach, we applied SPS in a backcrossing program which integrated MAS and speed breeding for the purpose of rapidly modifying the root system of elite bread wheat line Borlaug100. Bi-directional selection for root angle in segregating generations successfully shifted the mean root angle by 30o in the subsequent generation (P ≤ 0.05). Within 18 months, BC2F4:F5 introgression lines were developed that displayed a full range of root configurations, while retaining similar above-ground traits to the recurrent parent. Notably, the seminal root angle displayed by introgression lines varied more than 30° compared to the recurrent parent, resulting in lines with both narrow and wide root angles, and high and low root biomass phenotypes.Conclusion: The SPS approach enables researchers and plant breeders to rapidly manipulate root traits of future crop varieties, which could help improve productivity in the face of increasing environmental fluctuations. The newly developed elite wheat lines with modified root traits provide valuable materials to study the value of different root systems to support yield in different environments and soil types.

Change of the flowering pattern as a formula of success in pea breeding aimed at increasing the early ripeness and the yielding capacity of peas

Relevance. Most of the pea varieties used in the production of canned vegetables have similar morphological structure of the stalk: shortened internodes, their limited number and location in the upper part of the stalk. The deficiency of such plant architectonics is the limitation of yielding capacity in relation to small number of yielding nodes, yielding capacity instability, and high degree of affliction by plant diseases. The production of pea varieties having an increased number of yielding nodes will allow changing the relation between the nonproductive and reproductive parts to the advantage of the latter.Methods. The pea varieties from the collection of bean cultures laboratories of the Federal Scientific Vegetable Center were used as the research varieties. The main method of work was intervarietal hybridization with subsequent single plant selection. In 2018-2019 the selected lines were seeded in a nursery with an area of 7 m2 . The forms with changed flowering pattern (Pervenets, Ranniy 28-11, Wenson) and the most yielding early and midseason varieties (Dakota, Ranniy Gribovsky 11, Voronezhsky Zelyony, Korsar, Orus, Viola, Zelyonaya Strela, Quartella) were used as parent components. The selection was performed on the basis of the following features: changed flowering pattern, the number of yielding nodes, the number of legumes on a node, as well as the length of a bean and the number of seeds in a legume. A finometer was used for the determination of the green pea hardness.Results. Sample 50-4-19 having a relatively low number of yielding nodes (6, 9) had the highest characteristics and was considerably superior to all the other samples by its yielding capacity during the first and the second harvesting periods (7.24 and 9.55 tons per hectare). The selection of the early forms with the changed flowering pattern and the shift of the attraction centre to the 2nd or to the 3rd node allow carrying out breeding aimed at increasing the early ripeness and the yielding capacity of peas.

Intense Breeding within Lentil Landraces for High-Yielding Pure Lines Sustained the Seed Quality Characteristics

Landraces are a valuable source of genetic variability for breeders to develop high-yielding lentil varieties. Apart from productivity, simultaneous breeding for lentil seed nutritional quality is of paramount importance for wider lentil consumption. This work examined the indirect effect of single plant selection for high yield on important seed quality traits within three Greek lentil landraces (“Elassona” (EL), “Lefkada” (L), and “Evros” (EV)). The breeding methodology applied was proved to help either maintain or improve such characteristics in the high-yielding second-cycle lines (SLs) selected. Compared to the parental landrace “Elassona”, the high-yielding lines showed increased crude fiber by 30–110%; the line 2-SL-EL-6 had higher starch content by 3.9% and reduced cooking time by 6.67 min, while the 2-SL-EL-10 line had higher crude fiber by 73%. In the case of “Lefkada”, the high-yielding lines selected maintained the protein content present in the parental landrace, apart from the 2-SL-L-1 where a decrease by 5% was recorded; however, most of them showed increased crude fiber (5.59–7.52%) in comparison with the parental landrace (4.65%). Finally, in relation to the “Evros” parental landrace, the 2-SL-EV-3 and 2-SL-EV-4 showed higher crude fiber and reduced cooking time. This study provides evidence that proper management of genetic variability could improve productivity without compromising or sometimes improving some seed quality traits.

Studi Pola Segregasi Karakter Morfologi – Agronomi Tanaman Padi Hasil Persilangan Kultivar Pandan Ungu x Roti Pada F2

The efforts to increase rice production at East Borneo apart from the improvement of cultivation systems also could be done by using superior variety. Hybridization of rice plants has been done between the female local variety Pandan Ungu and the male local variety Roti. The research toward F2 progeny to find out the segregation patterns of inheritance of the characters number of tillers, plant height, stem leaves color, and palea-lemma color has been done at the paddy field at Desa Sidomulyo, Kecamatan Anggana, Kabupaten Kutai Kartanegara since October 2016 until March 2017. The F2 identification method that was used is single plant selection methods, based on Standard Evaluation Systems (SES) for Rice. Suitability test between observed value and expected value used Chi-square test, and to see the characters segregation pattern ratio used Mendelian genetics analysis. The inheritance character of stem leaves color was managed by two pairs of genes followed segregation ratio 9:6:1 with the action epistatic genes with cumulative effect, the inheritance of palea-lemma character was managed by two pairs of genes followed Mendelian ratio 13:3 with the action epistatic dominant-recessive, while the characters plant height and number of tillers was managed by polygenes so the inheritance patterns was not following Mendelian ratio.