Selekcija na uniformnost i stabilnost prinosa kukuruza

Historically speaking, both the introduction of double-cross hybrids and use of single crosses have caused the increase in grain yield and significantly improved agricultural practice. Nowadays, the uniformity of crops is regarded as an advantage of modern agriculture, since the uniformity of products is crucial in global market. Thus, uniformity of crop maturation provides both planning and efficient mechanized harvest. F1 single-cross hybrids of maize, which is an allogamous species, not only exploit heterosis, but also impose homogeneity. Basically, the uniformity of hybrids has been regarded as their crucial advantage. There are two aspects of hybrid maize uniformity: (i) genetic homogeneity and (ii) genetic stability. Genetic homogeneity refers to presence of identical genotypes, whereas genetic stability refers to phenotypic uniformity (homeostasis) in different environments. At present, yield performance of inbreds has not advanced as rapidly as performance of hybrids, especially in stressful environments. Focusing on inbred productivity combined with stability may be more appropriate strategy in the future. Poor farmers are not able to employ superior genotypes because they require considerable financial investment and farmers survive not due to high yield in good seasons, but due to enduring extreme ones. Breeding process may create genotypes in favorable seasons when genetic variance is maximal and environmental influence is minimal, which should be followed by breeding for different environments. The aim of such breeding are, most probably, genotypes intended for a specific set of conditions which, in fact, represents a convergence of two strategies of plant breeding. One should probably bear in mind the strategy of both yield improvement and survival of farmers in extreme conditions without decreasing yield of best genotypes, especially those adapted only to favorable conditions. Solution to this problem should be: financial (best possible loans), social (education), and technological (breeding improved genotypes and advanced agricultural production).Uniformnost useva se smatra poželjnom osobinom u modernoj poljoprivredi, jer je proizvod uniformnosti esencijalan na tržištu. Uniformnost u sazrevanju omogućuje planiranje biljne proizvodnje i efikasnu mehaničku žetvu i berbu. Osim toga, uniformnost useva je bitna za maksimalni prinos. Obzirom da je uniformnost malo praćena i analizirana postavili smo to za cilj u ovom radu. Uniformnost useva posebno postaje značajna osobina sa porastom i povećanjem značaja svetskog tržišta roba. Ona je redovno udružena sa smanjenjem diverziteta. Međutim, genetički diverzitet se može povećati gajenjem brojnih različitih homogenih sorata ili autohtonih populacija. Diverzitet useva se smatra poželjnim i bitnim u nekim klimatskim uslovima. Divergentne populacije koje su ranije zauzimale proizvodne kapacitete ublažavale su pad proizvodnje pod uticajem različitih stresnih uslova i na taj način smanjivale rizik. Gajenje uniformnih hibrida može rezultirati problemima u polinaciji kod kukuruza usled temperaturnog stresa koji je karakterističan u našem području. Diverzitet može biti povećan korišćenjem prirodnih populacija i gajenjem F1 hibrida sa različitom dužinom vegetacije kod kukuruza. Iz svega napred navedenog može se zaključiti da hibridi nisu najbolji za opstanak siromašnih farmera zbog značaja finansijskih ulaganja u seme i tehnologiju i opravdane zabrinutosti za nastali rizik usled gajenja neadaptiranih hibrida i smanjenja varijabilnosti kukuruza usled oplemenjivanja. Siromašni farmeri u ekstremnim uslovima održavaju genetički diverzitet kod različitih kultura i heterogenost sorata maksimalno adaptiranih datim uslovima u prostoru i vremenu. Preživljavanje u nepovoljnim godinama, ne prinos u povoljnim godinama je ključ opstanka siromašnih farmera. Ovo je verovatno važno za razvoj strategije u selekciji u cilju inkorporiranje gena za individualno ublažavanje posledica stresa inbred linija i hibrida. Za selekciju je bitno održavanje kontinuiranosti u potomstvu nosioca stabilnosti. Potomstvo može nastati selekcijom u povoljnim uslovima gde je genetička diferenciranost maksimalna, a uticaj spoljne sredine minimalan i oplemenjivanjem za različite uslove gajenja. Najverovatnije da je cilj selekcije stvaranje genotipova za date uslove spoljne sredine, što je u stvari približavanje napred navedena dva pristupa u selekciji. Ispitivanje i testiranje dobijenih genotipova mora imati ciljne uslove gajenja, lokacije. Možda pri razvoju strategije treba imati na umu strategiju povećanja prinosa i opstanka farmera u ekstremnim uslovima, pri čemu ne dolazi do smanjenja prinosa kod najboljih genotipova, naročito adaptiranih samo na povoljne uslove koji bi se sastojali u poboljšanju uslova i kulture proizvodnje istovremeno. Potencijalna solusija za ove probleme mora biti ekonomska (najbolje moguće kreditiranje) i socijalna (edukacija), kao i tehničko-tehnološka (poboljšanje genotipova i tehnologije gajenja)

Komponente genetičke varijabilnosti i heritabilnost prinosa zrna silažnog kukuruza

The aim of the present study was to evaluate the following parameters for the grain yield of silage maize: variability of inbred lines and their diallel hybrids, superior-parent heterosis and components of genetic variability and heritability on the basis of the diallel set. The two-year four-replicate trial was set up according to the randomized complete-block design at Zemun Polje. It was determined that a genotype, year and their interaction significantly affected variability of this trait. The highest. i.e. the lowest grain yield, on the average for both investigation years. was recorded in the silage maize inbred lines ZPLB402 and ZPLB405. respectively. The analysis of components of genetic variance for grain yield shows that the additive component (D) was lower than the dominant (H1 and H2) genetic variance, while a positive component F and the frequency of dominant (u) and recessive (v) genes for this observed trait point to prevalence of dominant genes over recessive ones. Furthermore. this is confirmed by the ratio of dominant to recessive genes in parental genotypes for grain yield (Kd/Kr> 1) that is greater than unity in both years of investigation. The estimated value of the average degree of dominance (H1/D)1/2 exceeds unity, pointing out to superdominance in inheritance of this trait in both years of investigation. Results of Vr/Vr regression analysis indicate superdominance in inheritance of grain yield. Moreover. a registered presence of non-allelic interaction points out to the need to study effects of epistasis, as it can have a greater significance in certain hybrids. A greater value of dominant than additive variance resulted in high values of broad-sense heritability for grain yield in both investigation years (98.71%, i.e. 97.19% in 1997, i.e. 1998, respectively). and low values of narrow-sense heritability (11.9% in 1997 and 12.2% in 1998).Pravilna procena heterozisa, genetičke varijabilnosti i heritabilnosti neke osobine je veoma bitna sa stanovišta praktične selekcije, što je i bio cilj ovih istraživanja. Rezultati analize varijanse pokazuju visoko značajne razlike između ispitivanih genotipova za prinos zrna. kao i značajan uticaj godine i interakcija godina x genotip na varijabilnost ove osobine. Najveći prinos zrna su imali hibridi ZPLB401 x ZPLB406 (1997) i ZPLB404 x ZPLB406 (1998). Hibridi su u odnosu na linije ispoljili veće prosečne vrednosti za prinos zrna što je i očekivano obzirom da pri inbridingu dolazi do depresije ove osobine kod linija. Za većinu hibridnih kombinacija utvrđene su visoke vrednosti heterozisa, dok je hibrid ZPLB402 x ZPLB403 pokazao negativnu vrednost heterozisa za prinos zrna (-11.0 do -31.7%). Analiza komponenti genetičke varijanse pokazuje da su dominantne komponente (H1 i H2) bile veće od aditivne (D) i imale važniju ulogu u nasleđivanju prinosa zrna u F, generaciji. Komponenta F je pozitivna za ovu osobinu što ukazuje da dominantni geni preovlađuju nad recesivnim. Izračunata vrednost prosečnog stepena dominacije (H1/D)1/2 je veća od jedinice za ovu osobinu i pokazuje da se u nasleđivanju ovih osobina radi o superdominaciji. Odnos dominantih gena prema recesivnim kod roditeljskih genotipova pokazuje da su kod prinosa zrna preovladavali dominantni geni nad recesivnim [Kd/Kr>l) u obe godine. Rezultati Vr/Vr regresione analize ukazuju na superdominaciju u nasleđivanju prinosa zrna. Prisustvo nealelne interakcije ustanovljeno je za ovu osobinu. To ukazuje na potrebu proučavanja efekta epistaze pošto može imati veći značaj kod pojedinih hibrida. Za prinos zrna su dobijene visoke vrednosti heritabilnosti u širem smislu (98.4% (1997) i 97.9% (1998)) i niske vrednosti heritabilnosti u užem smislu (11.9% (1997) i 12.2% (1998))

Molecular characterization of red clover genotypes utilizing microsatellite markers

Genetic resources of red clover (Trifolium pratense L.) are the basis for the improvement of this important forage legume. The objective of this study was microsatellite characterization of the accessions from the collection of the Institute of Field and Vegetable Crops in Novi Sad, Serbia. Molecular evaluation of 46 red clover genotypes was performed by applying the set of 14 primer pairs of microsatellite markers. These primer pairs amplified a total of 187 alleles, with an average of 13.36 alleles per locus and average polymorphism information content (PIC) value was 0.306. The minimum values of Dice genetic distances based on polymorphism of microsatellite markers were found among genotypes NCPGRU2 and NCPGRU5 (0.311) and the highest values of genetic distances were determined for a couple of genotypes Violeta and BGR2 (0.933). The average genetic distance between all pairs of genotypes amounted 0.587. The results of the principal coordinate analysis (PCoA) were consistent with the results obtained on the basis of cluster analysis, except that the PCoA allocated another four genotypes. There was no relationship between groups of genotypes formed by the use of cluster analyses and PCoA with their geographical origin. Analysis of molecular variance of 46 red clover genotypes by the status and ploidy level was significant, but it also suggested a weak genetic differentiation of groups formed on the basis of those characteristics. Observed groups of genotypes, according to the cluster analyses and PCoA of microsatellite data, could be used in future breeding programs for the selection of germplasm

Identifikacija donora poželjnih alela za prinos ploda hibrida k 35 x k 12 plavog paradajza

The aim of this study was to identify an eggplant donor line which possess the largest frequency of favorable alleles that control fruit yield. Such donor line should be used to improve the elite eggplant hybride K35 x K12. The fruit yield of the elite hybrid, its parents and their hybrids with three potential donor lines (K36/1, K11 and K22/2) was examined in a diallel set by means of field trials. The trials were set in a randomized block design in three replications. After the fruit yield had been measured, the modified method of evaluation of relative loci value according to Dudley (1987) was applied. Ali inbred lines expressed positive values of the μG' parameter. The K11 inbred had the largest μG' value (2.38) and, also, the lowest frequency of unfavourable alleles on the loci class D (1.33). It was established that the K11 inbred line was more related to the K35 parental inbred line (7.81). Consequently, on the basis of the μD' values, improvement should be obtained by backcrossing the elite hybrid K35 x K11 to the donor inbred K11.Cilj ovog rada je bio da se izdvoje one inbred linije plavog paradajza koje poseduju najveću frekvenciju poželjnih alela za prinos ploda. Ovakve linije bi mogle da se iskoriste za unapređenje elitnog hibrida plavog paradajza K35 x K12. Prinos ploda ovog elitnog hibrida, njegovih roditeljskih linija i tri potencijalna donora poželjnih alela je bio utvrđen dialelnim ukrštanjem. Poljski ogledi su bili postavljeni po slučajnom blok sistemu u tri ponavljanja. Radi identifikacije donora poželjnih alela, primenjen je modifikovan matematički model po Dudley-u (1987). Sve inbred linije su ispoljile pozitivne vrednosti parametra μG'. Linija K11 je imala najveću vrednost (μG' (2.38) i, takođe, najnižu frekvenciju nepoželjnih alela na klasi lokusa D (μD'= 1.33) a bila je i najbolji opšti kombinator (4.01"). Ova linija je bila srodnija roditeljskoj komponenti elitnog hibrida K35 (7.81). Na osnovu vrednosti parametra μD' poboljšanje prinosa ploda hibrida K35 x K12 bi trebalo postići unapređenjem roditeljske komponente K35. Pri tome, početnu populaciju za selekciju poboljšane linije K35, po našim rezultatima, treba zasnovati povratnim ukrštanjem elitnog hibrida K35 x K11 sa linijom K11 kao rekurentnim roditeljem i donorom poželjnih alela

Mega-sredine suncokreta u Srbiji prema GGE biplot analizi

Sunflower mega-environment analysis was conducted for the grain yield data of 20 hybrids and 19 test locations during 2006, and 20 hybrids and 16 test locations during 2007. Combined data included 15 hybrids and 9 test locations common for both years and it was analyzed as balanced experiment. The analysis of variance components showed that hybrid by location interaction explained 2.74, 5.8, and 3.72 times more variation than hybrid, for grain yield, for 2006, 2007, combined data, respectively, and indicated potential mega-environment existence. Our results showed the existence of two mega-environments in Serbia sunflower growing region: (1) Kula Vitovnica, Aleksa Šantić, Sombor and (2) Rimski Šančevi, Kikinda. It has been concluded that if we want promising sunflower hybrids to be optimally used, they should be cropped differently for the two determined mega-environments.Analiza mega-sredina suncokreta sprovedena je prema podacima prinosa zrna 20 hibrida i 19 test lokaliteta tokom 2006. i 20 hibrida i 16 test lokaliteta tokom 2007. Kombinovani podaci obuhvatili su 15 hibrida i 9 test lokaliteta, zajedničkih za obe godine istraživanja, pri čemu je analizirano kao izbalansirani eksperiment. Analiza komponenti varijanse pokazala je da interakcija hibrid puta lokalitet objašnjava 2,74, 5,8 i 3,72 puta više varijacija nego hibrid na prinos zrna za 2006. i 2007. u kombinovanim podacima, tim redom, i ukazuje na potencijalno postojanje mega-sredina. Naši rezultati su pokazali postojanje dve mega-sredine u reonima gajenja suncokreta u Srbiji: (1) Kula Vitovnica, Aleksa Šantić, Sombor i (2) Rimski Šančevi, Kikinda. Zaključeno je da ako želimo da perspektivni hibridi suncokreta budu optimalno iskorišćeni, moraju biti drugačije obrađeni za dve utvrđene mega-sredine

Izbor osobina za ocenu genetičke divergentnosti genotipova paradajza (lycopersicum esculentum mill)

On the basis of the seven tomato yield components (fruit length and width pericarp thickness, number of locules per fruit, number of fruits per plant fruit mass and frits mass per plant), six tomato genotypes were grouped into two clusters by applying the method of hierarchical cluster analysis. The values of the specific combining abilities (SCA) and heterosis effects in 15 tomato hybrids of F1 generation obtained by diallel crossing of six parental genotypes testified that the dendrogram of phenotypic differences was obtained on the basis of these features. It was concluded that the good hybrids with high SCA values and high heterosis effects were obtained by crossing the divergent genotypes of different clusters and high yielding genotypes of the same cluster. It was in conformity with the fact that the favourable gene recombining abilities and high heterosis effects were obtained by crossing the divergent parents and parents with the high accumulation of favourable genes for yield and yield components. Since this method was successfully applied and tested on six genotypes, it could also be applied for the characterisation and classification of the entire tomato germplasm collection. In such a way, the process of tomato selection would be greatly facilitated.Metodom hijerarhijske klaster analize izvršeno je grupisanje šest roditeljskih genotipova paradajza u dva klastera. Određivanje fenotipskih distanci vršeno je na osnovu sedam komponenti prinosa (dužine i širine ploda, debljine perikarpa ploda, broja komora ploda, broja plodova po biljci, mase ploda i mase plodova po biljci). Vrednosti posebnih kombinacionih sposobnosti (PKS) i heterozisa F1 hibrida dobijenih dijalelnim ukrštanjem između ispitivanih šest roditeljskih genotipova su poslužile za proveru pouzdanosti dobijenih fenotipskih distanci među ispitivanim genotipovima. Utvrđeno je da su dobri hibridi sa visokim PKS i visokim efektima heteroziza nastali ukrštanjem genotipova iz istih ili različitih klastera. To je u skladu sa činjenicama da se visok prinos može ostvariti ukrštanjem divergentnih genotipova. Kombinacione sposobnosti i heterozis bi trebalo proveravati za svaki konkretni slučaj kod paradajza. Pošto je metod uspešno primenjen i proveren na šest genotipova, može se primeniti i za karakterizaciju i klasifikaciju celokupne kolekcije germplazme paradajza za što veći broj osobina, čime se olakšava selekcija ove biljne vrste

Metode rekurentne selekcije i eksploatacija heterozisa kukuruza

Recurrent selection methods were designed to improve the agronomic value of populations by gradually increasing the frequency of favorable alleles, while maintaining genetic variability. To realize these objectives, progenies are developed, evaluated, selected and recombined in a repetitive manner. Populations improved by recurrent selection are excepted to be agronomically superior to unimproved versions and have enough genetic variability for the traits under selection to allow these populations be used for medium or long-term selection. The performance of hybrids is associated with the level of heterosis, i.e., to the superiority of hybrids over their inbred parents. To exploit heterosis efficiently, populations are grouped into heterotic groups, where population crosses within and among groups produce low and high levels of heterosis, respectively. Hybrids are then produced by crossing inbred lines from different heterotic group. Recurrent selection programs should be integrated with hybrid breeding programs so that improved populations can be used as sources of inbred lines not related to that ones developed from recycled lines via pedigree breeding. The objectives of this paper are to present the effects of recurrent selection on hybrid breeding programs; to present the changes in heterosis following recurrent selection; and to compare intra- and inter population recurrent selection. Testcross half-sib recurrent selection (TCHSRS) is for hybrid breeding programs, improvement of population crosses as well as the populations per se should be as efficient as possible, because their rates of improvement are approximately the same as for as the derived hybrids and inbred lines per se, respectively. The use of TCHSRS rather then RRS or HSRS would be the suitable strategy to accomplish the requirements of hybrid breeding programs. .Metode rekurentne selekcije imaju za cilj poboljšanje agronomskih vrednosti populacija uz postepeno povećanje frekvencije poželjnih alela osobina i održavanje genetičke varijabilnosti. U procesu selekcije neophodna je dovoljna genetička varijabilnost koja će omogućiti ovim populacijama da budu iskorišćene u procesu dugotrajnog oplemenjivanja. Stvaranje hibrida je u direktnoj vezi sa visokim heterozisom. Nivo heterozisa izmešu dve populacije je uslovljen njihovom genetičkom konstitucijom i divergentnošću. Inbred linije koje daju visok heterozis u hibridnim kombinacijama suporeklom iz različitih populacija, genetički udaljenih, koje čine heterotične parove. Cilj ovog rada je: (I) da pokaže efekte rekurentne selekcije pri stvaranju hibrida, (II) da pokaže promene u heterozisu pri različitim metodama rekurentne selekcije, (III) da uporedi razlike pri inter i intra populacijskoj rekurentnoj selekciji i (IV) da na osnovu ovih rezultata predloži novi modifikovani metod rekurentne selekcije. Obzirom na različitu efikasnost recipročne rekurentne selekcije (RRS) i half-sib rekurentne selekcije (HSRS) u inter i intra populacijskoj rekurentnoj selekciji, neophodno je primenjivati novi modifikovani metod rekurentne selekcije (test-cross half-sib rekurentnu selekciju, tj. TCHSRS). Ovaj metod selekcije u manjem procentu povećava heterozis nego RRS, ali poboljšanje međupopulacijskih hibrida i populacija per seje veće nego posle primene RRS i HSRS. TCHSRS metod se sastoji u tome da se jedna (prva) populacija koristi kao tester za drugu populaciju, te se poboljšava putem inter-populacijske rekurentne selekcije, dok se druga populacija poboljšava primenom intra-populacijske selekcije. Iz tih razloga ovaj modifikovani metod može biti nova strategija za postizanje savremenih zahteva u oplemenjivanju.

Effects of climatic factors on grain vitreousness stability and heritability in durum wheat

Modern durum wheat breeding programs are becoming more oriented toward creation of not only high-yield cultivars but also high quality, with good stability for the trait of interest. Vitreousness of grain is associated with semolina granulation, color, and protein content; it is regarded as one of the most important characteristics in the grading industry, affecting the commercial value of the commodity. A set of 15 winter and facultative durum wheat genotypes was tested for grain vitreousness across 6 environments for 2 consecutive years. Three-way analysis of variance showed that genotype, location, and year contributed 4.1%, 20.6%, and 42.2% to the total sum of squares, respectively. Interaction terms, including genotype, contributed 6.1% to the total sum of squares, and location x year contributed 27.0%. Stability of grain vitreousness for the examined breeding lines and cultivars of durum wheat was shown by the site's regression. Broad-sense heritability of grain vitreousness was estimated to be 71%. Climatic variables were used for factorial regression modeling, and most of the interaction term for grain vitreousness was explained by mean temperatures in June (54.4%) and April (14.2%), and precipitation (14.4%) and sunshine hours (14.3%) in March. During the grain filling and grain ripening stages, the most influential climatic variables in explaining interaction were maximum temperature (43.4%), precipitation (30.9%), and sunshine hours (5.6%)

Assessing wheat performance using environmental information

The partial least squares (PLS) regression model was applied to wheat data set with objective to determining the most relevant environmental variables that explained biomass per plant and grain yield genotype x environment interaction (GEI) effects. The data set had 25 wheat genotypes (20 landraces + 5 cultivars) tested for 4 years in two different water regimes: rainfed and drought. Environmental variables such as maximum soil temperature at 5 cm in April and May, soil moisture in the top 75 cm in March, and sun hours per day in May accounted for a sizeable proportion of GEI for biomass per plant. Similar results were obtained for grain yield: maximum soil temperature at 5 cm in April, May and June, and sun hours per day in May were related to the factor that explained the largest portion (>38%) of the GEI. Generally, wheat landraces are able to better exploit environments with higher temperatures and lower water availability during vegetative growth (March-June) than cultivars

Genetic diversity of alfalfa domesticated varietal populations from Libyan genbank revealed by RAPD markers

Alfalfa (Medicago sativa L.) is an important forage legume in Libya. The genetic diversity of nine alfalfa domesticated varietal populations was studied using thirteen RAPD primer combinations. The number of polymorphic fragments detected per primer combination ranged from 8 to 46 bands with an average of 24 bands. The number of polymorphic bands detected was from 6 (Atalia population) to 37 (Gabsia population). The lowest genetic distance was 0.058 and the highest was 0.655. The average genetic distance was (0.356). The dendrogram based on Ward's minimum variance clustering method grouped the nine populations into the two main clusters. The first group included Fazania, Atalia, Masratia, Zawia, Denamo Ferade and Arezona. The second group was composed of Tagoria, Gabsia and Wade Alrabeh. The simplicity of RAPD assays for detection of genetic polymorphisms is confirmed in our study, and results can be utilized in breeding practice