Effect of reciprocal crossing in partial interspecific lines stability and breeding of commercial varieties in cotton

Cotton is one of the most important crops both in Greece and worldwide. Modern demands of producers and industry as well as the needs of the ever-growing tertiary sector, contribute to the creation of competitive cotton varieties which will include all desired traits in one genotype. For this purpose, a production system of partial interspecific cotton lines was developed in the Laboratory of Genetics and Plant Breeding in the Aristotle University of Thessaloniki, originating from the pollination of Gossypium hirsutum x Gossypium barbadense hybrids with pollen from the species Hibiscus cannabinus. This effort eventually led to the isolation of genotypes with relatively high yields and excellent quality characteristics. The aim of this study was the exploitation of this genetic material in breeding experiments for the isolation of superior genotypes combining high yield and fiber quality traits with stability of performance. Initially, a three-year experiment was designed for the evaluation and selection of seven partial interspecific cotton lines. The experiments included the biennial evaluation of cotton lines in the absence of competition, according to honeycomb methodology and then the evaluation of selected genotypes in dense planting. The result of this effort was the identification of genotypes with stable performances (increased emergence capacity, morphological uniformity, and increased earliness), high yield and good fiber quality traits compared to commercial varieties that were used as controls. Besides, partial interspecific cotton lines were included in a program of reciprocal backcrosses with commercial cotton varieties aiming to improve the quality characteristics of commercial varieties and to increase the stability behavior of partial interspecific lines. The backcrosses were applied for three years and the progeny were evaluated separately in the absence of competition in two experiments (honeycomb designs R-13 and R-16). The selected genotypes were evaluated for another two years in dense planting. In general, the backcrosses of partial interspecific lines with commercial varieties seem to lead to some high-yielding genotypes with stable performance but slightly lower values for the fiber attributes compared to initial partial interspecific lines. Finally, the repeatability of the protocol used for the production of the partial interspecific hybrids through the pollination of the Gossypium hirsutum x Gossypium barbadense hybrids with pollen from the species H.cannabinus using new combination of commercial varieties as parents was checked and verified. This methodology creates new genetic variation since it leads to the effective integration of the genetic material of two species in one genotype, avoiding problems of previous methodology. Furthermore, SSR molecular markers were used for the molecular identification of the partial interspecific lines obtained and the study of the phylogenetic relationships among the partial interspecific hybrids, their respective parents, the F1 and F2 generations and their progeny Pa0 and Pa1. The results indicate that partial interspecific lines genetically differ from the products of self-pollination of the F1 interspecific hybrid.Το βαμβάκι αποτελεί μία από τις σημαντικότερες καλλιέργειες, τόσο στην Ελλάδα, όσο και σε παγκόσμιο επίπεδο. Οι σύγχρονες απαιτήσεις των παραγωγών και της βιομηχανίας, καθώς και οι ανάγκες του συνεχώς αναπτυσσόμενου τριτογενούς τομέα, συμβάλλουν στη δημιουργία ανταγωνιστικών ποικιλιών βαμβακιού, που θα συμπεριλαμβάνουν όλα τα επιθυμητά γνωρίσματα σε έναν γενότυπο. Στο Εργαστήριο Γενετικής και Βελτίωσης Φυτών του Αριστοτελείου Πανεπιστημίου Θεσσαλονίκης αναπτύχθηκε ένα σύστημα παραγωγής μερικώς διειδικών φυτών βαμβακιού, προερχόμενων από την επικονίαση υβριδίων Gossypium hirsutum x Gossypium barbadense με γύρη από το είδος Hibiscus cannabinus. Η προσπάθεια αυτή οδήγησε στην απομόνωση γενοτύπων με υψηλές αποδόσεις και άριστα ποιοτικά χαρακτηριστικά. Σκοπός της συγκεκριμένης εργασίας ήταν η αξιοποίηση του εν λόγω γενετικού υλικού σε πειράματα βελτίωσης, που θα οδηγήσουν στον εντοπισμό υπέρτερων γενοτύπων, οι οποίοι συνδυάζουν την υψηλή απόδοση και την εξαιρετική ποιότητα ίνας με τη σταθερότητα της συμπεριφοράς. Αρχικά, σχεδιάστηκε ένα τριετές πείραμα αξιολόγησης και επιλογής, με υλικό εκκίνησης επτά μερικώς διειδικές σειρές βαμβακιού. Τα πειράματα συμπεριλάμβαναν τη διετή αξιολόγηση των σειρών, σε κυψελωτή διάταξη, απουσία ανταγωνισμού, και στη συνέχεια την αξιολόγηση των γενοτύπων που διακρίθηκαν, σε συνθήκες πυκνής σποράς. Το αποτέλεσμα της προσπάθειας αυτής ήταν η εκκαθάριση του αρχικού γενετικού υλικού, που οδήγησε στην απομόνωση γενοτύπων με σταθερότητα παραγωγικής συμπεριφοράς (αύξηση της φυτρωτικής ικανότητας, μορφολογική ομοιομορφία, αύξηση πρωιμότητας), υψηλές αποδόσεις και εξαιρετική ποιότητα, σε σχέση με τις εμπορικές ποικιλίες-μάρτυρες. Παράλληλα, οι μερικώς διειδικές σειρές βαμβακιού συμπεριλήφθησαν και σε ένα πρόγραμμα αμοιβαίων αναδιασταυρώσεων με εμπορικές ποικιλίες βαμβακιού, με σκοπό τη βελτίωση των ποιοτικών χαρακτηριστικών των εμπορικών ποικιλιών και την αύξηση της σταθερότητας συμπεριφοράς των μερικώς διειδικών σειρών. Οι αναδιασταυρώσεις εφαρμόστηκαν για τρία έτη και οι απόγονοι των αναδιασταυρώσεων αξιολογήθηκαν ξεχωριστά, απουσία ανταγωνισμού, σε δύο πειράματα (κυψελωτή διάταξη R-13 και R-16, αντίστοιχα). Οι γενότυποι που επιλέχθηκαν αξιολογήθηκαν τελικά για δύο έτη, σε συνθήκες πυκνής σποράς. Σε γενικές γραμμές, οι αναδιασταυρώσεις των μερικώς διειδικών σειρών με τις εμπορικές ποικιλίες φαίνεται να οδηγούν σε ορισμένους υψηλοαποδοτικούς γενοτύπους, με ελαφρώς χαμηλότερες τιμές για τα γνωρίσματα της ίνας σε σχέση με αυτές που παρουσίαζαν οι μερικώς διειδικές σειρές, αλλά με υψηλότερη σταθερότητα συμπεριφοράς. Τέλος, ελέγχθηκε και επιβεβαιώθηκε η επαναληψιμότητα του πρωτοκόλλου παραγωγής των μερικώς διειδικών υβριδίων μέσω της επικονίασης υβριδίων Gossypium hirsutum x Gossypium barbadense με γύρη από το είδος H. cannabinus, επιλέγοντας νέους συνδυασμούς ποικιλιών ως γονείς. Η συγκεκριμένη μεθοδολογία δημιουργεί νέα γενετική παραλλακτικότητα, αφού οδηγεί στην αποτελεσματική ενσωμάτωση του γενετικού υλικού των δύο ειδών σε έναν γενότυπο, χωρίς τα προβλήματα που παρουσιάζουν οι παλαιότερες μεθοδολογίες. Επίσης, χρησιμοποιήθηκαν μοριακοί δείκτες τύπου SSR για τη μοριακή ταυτοποίηση των μερικώς διειδικών σειρών που προέκυψαν, και τη διερεύνηση των φυλογενετικών σχέσεων ανάμεσα στα μερικώς διειδικά υβρίδια, τους αντίστοιχους γονείς, τις F1 και F2 γενεές, αλλά και τους απογόνους Pa0 και Pa1. Τα αποτελέσματα αποτελούν ένδειξη ότι τα μερικώς διειδικά υβρίδια διαφέρουν γενετικά από τα προϊόντα της αυτογονιμοποίησης του συγκεκριμένου υβριδίου (F1 γενεά)

Intercropping grain-legumes and cereals for improved protein concentration in the cereal (ReMIX Practice abstract)

Outcome: Mixed cropping systems achieve higher protein content of bread wheat, with no need to include nitrogen (N) fertilizers. Practical recommendations: - The seed bed should not be too fine-grained after cultivation. - Test soil samples and amend P and K levels, if necessary. - Select cultivars (wheat and grain legume) with the same maturity time according to local seed costs and market availability. - Mix the seeds 70% grain legume and 30% wheat relative to the standard sowing quantities of the crops in the seed tank. Check that the mixture is homogenous and sow with a conventional seeder. - Use the recommended row spacing of the cereal crop. - Apply weed control as needed (organic or conventional). - Adjust the height of the harvester to pick up grain legumes close to ground. Practical testing/ Farmers’ experiences: If this crop system seems suitable for you, we recommend that you test this under your conditions. Separate a part of your field before sowing and apply the mixture. Cultivate the rest of the field as usual and compare the intercrop to the pure stand cereals and/or legumes crops

Seed Rate and Cultivar Effect on Contribution of Vicia sativa L. Green Manure to Soil Amendment under Mediterranean Conditions

The performance of Vicia sativa L. cultivars and cultivar mixtures used as green manure under two seed rates in a Mediterranean environment was investigated in a split plot design, over the period 2014–2016. Six common vetch cultivars grown in pure stands or in mixtures were established at two seed rates (S1 = 100 Kg ha−1 and S2 = 180 kg ha−1). Growth traits (e.g., plant height, biomass yield, LAI, CGR) were monitored until incorporation into topsoil. The nitrogen (N) concentration of the incorporated biomass along with the decomposition rate were determined, and the effects on the N supply to the soil were evaluated two, four and six months after biomass incorporation. The increment in residual soil Ν four months after green manuring fluctuated from 17 to 45 kg ha−1 among cultivars, and after six months, from 22 to 50 kg ha−1. The average decomposition rate of organic substances was slightly higher for S2 for all time intervals; however the highest value (62.6%) was recorded for S1 six months after biomass incorporation. Seed rate-independent genotypes were identified with regard to the decomposition of organic matter and are suggested as being suitable for green-manuring farming systems with a low seed rate, a fact that offers options with economic and environmental benefits

Testing the Validity of CV for Single-Plant Yield in the Absence of Competition as a Homeostasis Index

The coefficient of variation (CV) of yield may functionally be related to the mean. The expected exponential CV decline with increasing mean, i.e., the Taylor’s power law (TPL), is not always valid. Removal of this scale dependency allows for a scale-independent assessment of stability. The objective of this study was to interpret the validity of the homeostasis index (HI), i.e., the inverse CV value, suggested in breeding under nil competition as a selection criterion for progeny lines that oppose the acquired interplant variation. Data concerning the single-plant yield of various crops under a nil-competition regime were studies against the theoretical background of the above hypothesis. Simple correlations between logarithms of variances and respective means were used to assess the reliability of CV as a stability statistic in breeding trials under nil competition. A total of 8 of the 24 case analyses revealed a systematic variance dependence on the mean. The impact was more prevalent in experiments with extensive spatial heterogeneity and high CV scores. Conversion of variance to remove systematic dependence did not validate the CV~mean negative relationship. Because of variance dependence, caution is needed when interpreting the HI as a stability index. Misuse of the HI may entail the risk of bias, upgrading or downgrading a progeny line in its ability to withstand acquired dissimilarity between plants. Testing the validity of the variance seems necessary, and the calculation of HI on a converted variance may enhance the accuracy of identifying the most promising progeny lines

The 4C Approach as a way to understand species interactions determining intercropping productivity

Modern agriculture needs to develop transition pathways toward agroecological, resilient and sustainable farming systems. One key pathway for such agroecological intensification is the diversification of cropping systems using intercropping and notably cereal-grain legume mixtures. Such mixtures or intercrops have the potential to increase and stabilize yields and improve cereal grain protein concentration in comparison to sole crops. Species mixtures are complex and the 4C approach is both a pedagogical and scientific way to represent the combination of four joint effects of Competition, Complementarity, Cooperation, and Compensation as processes or effects occurring simultaneously and dynamically between species over the whole cropping cycle. Competition is when plants have fairly similar requirements for abiotic resources in space and time, the result of all processes that occur when one species has a greater ability to use limiting resources (e.g., nutrients, water, space, light) than others. Complementarity is when plants grown together have different requirements for abiotic resources in space, time or form. Cooperation is when the modification of the environment by one species is beneficial to the other(s). Compensation is when the failure of one species is compensated by the other(s) because they differ in their sensitivity to abiotic stress. The 4C approach allows to assess the performance of arable intercropping versus classical sole cropping through understanding the use of abiotic resources

Seed Yield, Crude Protein and Mineral Nutrients of Lentil Genotypes Evaluated across Diverse Environments under Organic and Conventional Farming

Lentil is an important legume crop for human and animal dietary needs due to its high nutritional value. The effect of genotype and growing environment was studied on seed yield (SY), crude protein (CP) and mineral nutrients (macro and micronutrients) of five lentil genotypes grown at four diverse locations for two consecutive years under organic and conventional farming. The location within each year was considered as a separate environment (E). Data were subjected to over environment two-way analysis of variance, while a genotype (G) plus genotype × environment (GGE) biplot analysis was performed. Our results indicated the E as the main source of variation (62.3–99.8%) for SY, CP and macronutrients for both farming systems, while for micronutrients it was either the E or the G × E interaction. Different environments were identified as ideal for the parameters studied: E6 (Larissa/Central Greece/2020) produced the higher CP values (organic: 32.0%, conventional: 27.5%) and showed the highest discriminating ability that was attributed to the lowest precipitation during the crucial period of pod filling. E7 (Thessaloniki/Central Macedonia/2020) and E8 (Orestiada/Thrace/2020) had fertile soils and ample soil moisture and were the most discriminating for high micronutrient content under both farming systems. Location Orestiada showed the highest SY for both organic (1.87–2.28 t ha−1) and conventional farming (1.56–2.89 t ha−1) regardless the year of cultivation and is proposed as an ideal location for lentil cultivation or for breeding for high SY. Genotypes explained a low percentage of the total variability; however, two promising genotypes were identified. Cultivar “Samos” demonstrated a wide adaptation capacity exhibiting stable and high SY under both organic and conventional farming, while the red lentil population “03-24L” showed very high level of seed CP, Fe and Mn contents regardless E or farming system. This genetic material could be further exploited as parental material aiming to develop lentil varieties that could be utilized as “functional” food or consist of a significant feed ingredient

Plant Yield Efficiency by Homeostasis as Selection Tool at Ultra-Low Density. A Comparative Study with Common Stability Measures in Maize

The study pertains to field experimentation testing seven maize (Zea mays L.) hybrids at four densities, across five locations under normal (NIR) and low-input (LIR) regimes. The main objective was to assess the prognostic value of plant yield efficiency by homeostasis (PYEH) for breeding purposes at ultra-low plant density to predict hybrid yield potential and stability. PYEH comprises plant yield efficiency (PYE) that reflects the ability of individual plants to exploit resources, and plant yield homeostasis (PYH) that indicates the crop’s ability to evade acquired plant-to-plant variability. The same hybrids were also evaluated for stability by commonly used parametric and non-parametric statistics based on data at low (LCD) and high crop densities (HCD). Hybrid stability focused on potential yield loss due to erratic optimum density (OD). Most methods produced conflicting results regarding hybrid ranking for yield and stability especially at LCD. In contrast, PYEH consistently highlighted high-yielding and stable hybrids, potentially able to reach the attainable crop yield (ACY) inter-seasonally irrespective of crop spacing. Low density is common practice under resource-deficit conditions, so crop adaptation to crop spacing is a viable option to overcome erratic OD that constitutes a root source of crop instability in rainfed maize. The results were further supportive of breeding at ultra-low density to facilitate the identification and selection of superior genotypes, since such conditions promote phenotypic expression and differentiation, and ensure repeatability across diverse environments

Identification of the Optimum Environments for the High Yield and Quality Traits of Lentil Genotypes Evaluated in Multi-Location Trials

Lentil is a versatile and profitable pulse crop with high nutritional food and feed values. The objectives of the study were to determine suitable locations for high yield and quality in terms of production and/or breeding, and to identify promising genotypes. For this reason, five lentil genotypes were evaluated in a multi-location network consisting of ten diverse sites for two consecutive growing seasons, for seed yield (SY), other agronomic traits, crude protein (CP), cooking time (CT) and crude protein yield (CPY). A significant diversification and specialization of the locations was identified with regards to SY, CP, CT and CPY. Different locations showed optimal values for each trait. Locations E4 and E3, followed by E10, were “ideal” for SY; locations E1, E3 and E7 were ideal for high CP; and the “ideal” locations for CT were E3 and E5, followed by E2. Therefore, the scope of the cultivation determined the optimum locations for lentil cultivation. The GGE-biplot analysis revealed different discriminating abilities and representativeness among the locations for the identification of the most productive and stable genotypes. Location E3 (Orestiada, Region of Thrace) was recognized as being optimal for lentil breeding, as it was the “ideal” or close to “ideal” for the selection of superior genotypes for SY, CP, CT and CPY. Adaptable genotypes (cv. Dimitra, Samos) showed a high SY along with excellent values for CP, CT and CPY, and are suggested either for cultivation in many regions or to be exploited in breeding programs

Genotype X Environment Interaction Analysis of Faba Bean (Vicia faba L.) for Biomass and Seed Yield across Different Environments

Development of high yielding and stable cultivars of various legume crops across different environments is very important for their adoption by farmers. In addition, climate change sets new challenges to major crop species and especially to grain legumes such as faba bean (Vicia faba L.) for adaptation to stressful environments. The present study focused on evaluating faba bean genotypes developed for yield and stability across different environments. The study was conducted in three areas of Greece (South, Central, and North) for two consecutive growing seasons (2018–2019 and 2019–2020). Biomass yield, seed yield, and yield components were studied together with plant height, earliness, and water use efficiency. Genotype, environment, and their interaction affected most of the studied characteristics. The environment was the major source of variation for most of the characteristics, as it explained 81–93% of total variation, and only in the thousand seed weight the variation was 49% for the environment and 40% for the genotype. Genotype had a much smaller effect on the remaining characteristics (1.2–3.9%), and the interaction between environment x genotype accounted for up to 0.5–17% of the variation. GGE-biplot analysis for high yield and stability across different environments revealed three genotypic types: genotypes well adapted either for biomass or seed yield and genotypes with high adaptation capacity for both traits under typical Mediterranean conditions. These results indicated that screening faba bean genotypes under different environmental field conditions is essential to identify adaptable cultivars to be cultivated for biomass and/or seed yield or to be used in breeding programs