Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a certain trait, the following specific procedures in evaluation of the trait are necessary: the estimation of a popping volume and flake quality in popping maize; the determination of sugars and harvest maturity in sweet maize; the determination of oil in selected samples of high-oil maize types, and so forth. Breeding programmes for speciality maize, except high-amylose maize, have been implemented at the Maize Research Institute, Zemun Polje, Belgrade, for the last 45 years. A great number of high-yielding sweet maize hybrids, popping maize, high-oil and high-lysine, flint and white-seeded maize hybrids were developed during this 45-year period. Auspicious selection and breeding for these traits is facilitated by the abundant genetic variability and technical and technological possibilities necessary for successful selection

Effect of endosperm mutants on maize seed germination

The expression of genetic potential of yielding and quality of a certain genotype depends among other factors on seed quality. Seed is very important not only for the reproduction of the particular plant species, but also, for the contemporary plant production. Each part of maize seed (pericarp endosperm and germ) has a specific function in the complex process of germination and emergence. The following three genotypes of different endosperm types were observed: ZPSC 42A (standard grain quality dent hybrid) ZPSC 504 su (sweet maize hybrid with a sugary gene) and ZPSyn.II sh2 (synthetic population with a shranken2 gene). Seed viability of the stated genotypes was determined by the accepted ISTA methods: standard method accelerating age and cold test. Obtained results point out to differences in the germination capacity of the observed genotypes. The greatest reduction of the germination capacity and the emergence rate was expressed by the application of the accelerating ageing method. Appeared differences are probably a result of the endosperm texture (type), grain weight, sugar content and pericarp thickens and composition

Odnos prinosa i kvaliteta zrna hibrida kukuruza kokičara (Zea mays everta Sturt.)

Popcorn breeding programs develop at the same time in two directions with equal significance. One of them is producing higher yielding hybrids and the other is developing hybrids with higher popping volumes. The experiment was arranged in a randomized complete block design with four replications over three locations. Three traits were analyzed, grain yield, popping expansion and No. of kernals per 10g. ANOVA showed very significant influence of genotype, location and interaction of G x L, for all three traits. This points out that those traits are not influenced only by genetic factors, but also by environmental factors and the interaction of those two factors. Spearman’s correlation coefficient was established between examined traits. All correlations were negative and non significant. Nevertheless, especially correlation between grain yield and popping volume (rp-z=-0.10) indicated that hybrids with higher yields produced lower popping volumes. This once more concluded that breeding of popcorn is very complex process, for there is a necessity for high yielding and good popping quality hybrids.Oplemenjivanje kukuruza kokičara odvija se sa istom značajnošću u dva smera: povećanja prinosa zrna i povećanja zapremine iskokanog zrna. Prinos kao najvažnija ekonomska karakteristika kod svih kultura u slučaju kukuruza kokičara je u istom rangu kao i osobina zapremina kokičavosti. Ogled sa 12 hibrida kukuruza kokičara postavljen je po principu slučajnog bloka u četiri ponavljanja na tri lokacije. Ispitivane su osobine prinos zrna kukuruza, zapremina kokičavosti i broj zrna u 10 g. Analiza varijanse pokazala je visoku značajnost lokacije, genotipa i interakcije ova dva faktora za sve tri osobine. Ovo ukazuje na činjenicu da su posmatrane osobine pod uticajem ne samo genetičkih faktora, već i pod velikim uticajem faktora sredine kao i interakcije genotip x sredina. Utvrđena je korelacija između posmatranih osobina, pomoću Spaerman-ovog koeficijenta korelacije ranga. Negativna korelacija bila je između prinosa i zapremine kokičavosti r(p-z)= -0,1, koja iako nije bila statistički značajna ukazuje na to da prinosniji hibridi kukuruza kokičara daju zrno manje zapremine kokičavosti. Ovakvi rezultati govore u prilog kompleksnosti procesa oplemenjivanja kukruza kokičara, budući da su zahtevi postavljeni i u smislu povećanja prinosa i povećanja zapremine kokičavosti

Nasleđivanje i korelacija prinosa klipa i randmana zrna kod kukuruza šećerca (Zea mays L. saccharata)

In the present study, the mode of inheritance and combining abilities of six sweet maize inbred lines for ear yield and shelling percentage were observed by the method of diallel analysis. Estimates of general (GCA) and specific (SCA) combining abilities were highly significant (p lt 0.01) for both observed traits. Dominant gene effects were more significant for ear yield, while additive gene effects were more important for shelling percentage. Significant GCA for ear yield was observed only for L4, which also showed high potential in hybrid combinations with significant SCA estimates. For shelling percentage, significant GCA estimates were observed for L1 and L2, and these inbreds were also components of hybrids with significant SCA estimates. The correlation between ear yield and shelling percentage was highly significant (0.58**) among observed genotypes, showing a positive, medium high correlation and pointing out to the fact that high yielding genotypes also have high shelling percentage and vice versa.U radu je metodom dialelnog ukrštanja (6x6) proučavan način nasleđivanja i kombinacione sposobnosti šest samooplodnih linija kukuruza šećerca (L1-L6) za svojstva prinos klipa kukuruza i randman zrna. Analizom varijanse kombinacionih sposobnosti utvrđena je visoka značajnost vrednosti opštih (OKS) i posebnih kombinacionih sposobnosti (PKS) za oba svojstva. Presudan uticaj neaditivnog delovanja gena utvrđen je za nasleđivanje prinosa klipa, dok je za randman zrna aditivno delovanje gena bilo značajnije. Značajna vrednost OKS linija za prinos klipa kukuruza šećerca utvrđena je samo kod linije L4, koja se pokazala i kao dobar kombinator u hibridnim kombinacijama sa visokim vrednostima PKS. U slučaju randmana zrna visokoznačajne vrednosti OKS utvrđene su za linije L1 i L2, koje su takođe bile komponente hibrida sa visokoznačajnim vrednostima PKS. Koeficijentom korelacije ranga utvrđena je visokoznačajna vrednost (0,58**) između prinosa klipa i randmana zrna kukuruza šećerca, što ukazuje na srednje jaku zavisnost između ova dva svojstva i činjenicu da posmatrani genotipovi kukuruza šećerca koji se odlikuju visokim prinosom imaju i veći randman zrna i obratno

Varijabilnost prinosa i parametara kvaliteta zrna hibrida kukuruza kokičara (Zea mays L. Everta)

The experiment with 12 popcorn hybrids was set up according to the RCB design in three replicates. Examined traits were: grain yield (GY), popping volume (PV) and number of kernels per 10g (NK). ANOVA showed statistical differences among examined genotypes according to all three traits. Grain yield of the hybrids varied from 3.36 t/ha (ZPSK 645/1k) up to 6.07 t/ha (ZPSK 611k). The lowest popping volume had hybrid ZPSK 501k (27.33 cm3/g), which is considered unsatisfactory, while five hybrids had good popping volume over 38.00 cm3/g. Negative correlation was determined between GY and PV (-0.52), which although wasn't significant indicated that higher yielding hybrids often have lower popping volumes. Significant correlation was between GY and NK (-0.70*), and between NK and PV (0.66*). These results point out to the fact that breeding of popcorn is very complex process, for there is necessity of producing high yielding and good popping quality hybrids, which is mostly contradictory.Definisanje visokog kvaliteta kukuruza kokičara zavisi od aspekta kako proizvođača, dorađivača tako i potrošača. Zbog toga se posebna pažnja u oplemenjivanju kukuruza kokičara posvećuje povećanju prinosa, ali sa zadržavanjem i povećanjem kvaliteta iskokaknog i neiskokanog zrna. Ogled sa 12 hibrida kukuruza kokičara postavljen je po principu slučajnog bloka u 3 ponavljanja. Ispitivane su osobine: prinos zrna kukuruza, zapremina kokičavosti i broj zrna u 10 g. Analiza varijanse pokazala je da postoje statistički značajne razlike između posmatranih genotipova u pogledu sve tri osobine. Prinos zrna hibrida u ovom istraživanju, kretao se od 3,36 t/ha (ZPSK 645/1k) do 6,07 t/ha (ZPSK 611k). Najmanju zapreminu ostvario je hibrid ZPSK 501k (27,33 cm3/g), što se smatra izuzetno niskom zapreminom, dok je 5 hibrida imalo dobru zapreminu kokičavosti od preko 38,00 cm3/g. Najvišu zapreminu kokičavosti ostvario je ZPSK 649/1k sa 39,50 cm3/g. Šest hibrida iz ovog istraživanja imalo je krupno zrno, pet hibrida je bilo srednje krupnoće zrna, dok je hibrid ZPSK 501k (83 zrna u 10 g) bio sitnog zrna. Negativna korelacija utvrđena je između prinosa i zapremine kokičavosti (-0,52), koja iako nije bila značajna ukazuje na srednju jačinu zavisnosti između parametara i na to da prinosniji hibridi uglavnom imaju manju zapreminu kokičavosti. Značajna negativna korelacija utvrđena je između prinosa i broja zrna u 10 g (-0,70*), dok je značajna pozitivna korelacija bila je između broja zrna u 10 g i zapremine kokičavosti (0,66*). Ovakvi rezultati govore u prilog komleksnosti procesa oplemenjivanja kukuruza kokičara

Yields of ZP sweet maize hybrids in dependence on sowing densities

Sweet maize differs from maize of standard grain quality by many important traits that affect the ear appearance, and especially by traits controlling taste. The ear appearance trait encompasses the kernel row number, configuration, row pattern (direction and arrangement), seed set, kernel width and depth, ear shape and size. The quality of immature kernels is controlled by genes by which sweet maize differs from common maize. In order to obtain high-ranking and high-quality yields, it is necessary to provide the most suitable cropping practices for sweet maize hybrids developed at the Maize Research Institute, Zemun Polje. The adequate sowing density is one of more important elements of correct cropping practices. The objective of the present study was to determine the effect of four sowing densities in four ZP sweet maize hybrids of different FAO maturity groups on ear qualitative traits and yields obtained on chernozem type of soil in Zemun Polje. The observed traits of sweet maize (ear length, kernel row number, number of kernels per row, yield and shelling percentage) significantly varied over years. The higher sowing density was the higher yield of sweet maize was, hence the highest ear yield of 9.67 t ha-1 , on the average for all four hybrids, was recorded at the highest sowing density of 70,000 plants ha-1. The highest yield was detected in the hybrid ZP 424su. The highest shelling percentage (67.81%) was found in the hybrid ZP 521su at the sowing density of 60,000 plants ha-1. Generally, it can be stated that sweet maize hybrids of a shorter growing season (FAO 400) could be cultivated up to 70,000 plants ha-1, while those of a longer growing season (FAO 500) could be grown up to 60,000 plants ha-1. In such a way, the most favorable parameters of yields and the highest yields can be obtained

Oplemenjivanje kukuruza šećerca (Zea mays L. Saccharata) u Institutu za kukuruz Zemun polje

Sweet corn breeding programme have been implemented at the Maize Research Institute, Zemun Polje - Belgrade, for the last 40 years. Sweet corn is used as human food at the milk stage when the kernel is sweet, soft and succulent. It is one of the most popular vegetable crops in countries where maize consumption is traditional. Sweet corn is the mutant. The mutation at the Su lokus probably occurred at different time and in different types of maize. The su mutation affects the endosperm composition by causing it to accumulate two or more times water-soluble polysaccharides (WSP) then normal field corn has at the immature stage when it is normally consumed. Sucrose is predominant sugar in grain of standard sweet corn. Sweet corn is harvested 18-23 days after pollination. The homozygous recessive su gene has its limitations, and the major one is the very short period when kernels remain at high quality. Sometimes this period is as short as one day, which makes problems for sweet corn growers and processors. The identification of additional endosperm genes causing a higher level of sugar, leds to utilization of these genes in the development and improvement of sweet corn. Most sweet corn commercial hybrids are based on one or more recessive alleles which modify endosperm composition. These mutants are enzymic "injuries" in the path way of starch synthesis, which change endosperm carbohydrate composition and result, almost in all causes, in decreased starch level. The hybrids with the sh, sh2, bt, bt2 gene contain two to three times more sucrose than hybrids with the su gene. As a result the kernels (seeds) are of poor quality, winkled, light, angular, brittle and susceptible to injuries. Consequently, germination and emergence in the field, as well as, early growth, are harder than of standard grain quality maize. The aim of sweet corn breeders is to develop hybrids which will meet the demands of the market.Rad na oplemenjivanju kukuruza šećerca započet je sedamdesetih godina u Institutu za kukuruz "Zemun Polje". Do sada je priznato 20 ZP hibrida kukuruza šećerca različite dužine vegetacije. Svi domaći ZP hibridi kukuruza šećerca su sa sugary genom. U našoj zemlji najveći deo proizvedenog šećerca se prerađuje u obliku zamrznutog zrna. Standardni kukuruz šećerac je mutant. Mutacija su uslovljava takvu kompoziciju endosperma gde se akumulira dva puta i više u vodi rastvorljivih polisaharida (WSP) nego kod običnog kukuruza u fazi nezrelog zrna kada se ono konzumira. Ukus šećerca određuje slatkoća koja zavisi od udela šećera i skroba u endospermu. Ove osobine menjaju važnost zavisno od načina korišćenja hibrida. Glavni resursi u selekciji šećerca su elitni hibridi i elitne inbridovane linije, koji se preporučuju i odabiraju za poboljšanje osobina, kao i sintetičke populacije uže i šire genetičke osnove. Mnogi selekcionari šećerca se uzdržavaju od korišćenja germplazme koje nisu šećerac u svojim selekcionim programima zbog teškoća da se sačuva niz faktora kvaliteta i specifičnost sirovog proizvoda što je karakteristič no za šećerac. Naravno, germplazma koja nije u tipu šećerca se koristi za poboljšanje šećerca od samih početaka selekcionih programa. Ovaj tip germplazme se koristi kao izvor za povećanje relativne otpornosti prema bolestima i štetočinama u zavisnosti od aktuelnosti određenog svojstva za šećerac

Vizuelna ocena fenotipa linija kukuruza šećerca, po UPOV deskriptoru, kao pokazatelj heterozisa

The organisation of germplasm into genetically divergent groups is of extreme importance for the development of hybrid varieties in which the identification and exploitation of heterosis is very important for the final result of breeding. It can also be beneficial for breeding of self-pollination varieties, clones and synthetics. The discovery of heterotic groups in standard grain quality maize significantly improved the process of testing. The improvement in sweet maize was relatively modest in comparison to standard grain quality maize due to a relatively narrow genetic base of sweet maize, then poorly defined heterotic relations, scarce sources of germplasm that satisfy commercial standards, poor seed vigour, low quality of root and stalk, as well as, a short period of time for the estimation of yield and quality. The efficiency of hybrid breeding programmes would be significantly higher if heterosis could be predicted prior to the evaluation in the field. The application of the multivariate analysis method to data of phenotypic characterization according to the UPOV Descriptor was an attempt to establish whether such a procedure can be beneficial for the determination of related groups and whether the phenotypic distance, obtained on the basis of a visual estimation of a plant group, can be an indicator of heterosis. Obtained results indicate that clustering is highly analogous to the pedigree. Since sweet maize breeders have at their disposal less significant genetic variability and search for the development and defining of heterotic groups, as such a procedure can be useful in both, the process of the hybrids development and the process of new inbreed development and genetic variability increasing. Certainly, further systematic studies aimed at this direction are necessary to reliably ascertain that the phenotypic distance is a justifiable indicator of heterosis.Organizacija germ-plazme u genetički divergentne grupe je od izuzetne važnosti prilikom stvaranja hibridnih sorti, gde je identifikacija i iskorišćavanje fenomena heterozisa veoma važno za krajnji ishod oplemenjivanja. Ali takođe može biti od pomoći u oplemenjivanju slobodno oprašujućih sorti, klonova i sintetika. Otkriće heterotičnih grupa kod standardnog kukuruza je znatno unapredilo proces testiranja. Kod kukuruza šećerca, elativno uska genetička osnova, malobrojni izvori germ-plazme koji zadovoljavaju komercijalne standarde, slaba životna sposobnost semena, loš kvalitet korena i stabla kao i kratak period za ocenu prinosa i kvaliteta su razlozi relativno skromnog unapređenja prinosa u poređenju sa standardnim kukuruzom. Efikasnost hibridnih oplemenjivačkih programa bi se znatno moga povećati ako bi bilo moguće predvideti heterizis pre evaluacije u polju. Primenjujući multivarijacione metode statistike na podatke fenotipske karakterizacije po UPOV deskriptoru pokušano je da se istraži da li ovakva procedura može biti od pomoći prilikom određivanja grupa po srodnosti i da li fenotipska distanca, dobijena na osnovu vizuelne ocene grupe biljaka, može biti indikator heterozisa. Dobijeni rezultati ukazuju da postoji grupisanje koje je u visokoj saglasnosti sa pedigreom. Kako oplemenjivači kukuruza šećerca imaju na raspolaganju manju genetičku varijabilnost i u potrazi su za razvojem i definisanjem heterotičnih grupa, ovakva procedura može biti od koristi kako u procesu stvaranja hibrida tako i u procesu stvaranje novih linija i povećanja genetičke varijabilnosti. Svakako da su sistematska istraživanja u ovom pravcu potrebna da bi se moglo sa pouzdanošću tvrditi da je fenotipska distanca pouzdan indikator heterizisa

Oplemenjivanje kukuruza šećerca za različite načine potrošnje

Sweet maize is consumed as human food in the milk stage of the endosperm development when the kernel is soft, sweet and succulent. The highest number of commercial sweet maize hybrids is based on one or more recessive alleles that alter a carbohydrate content of the endosperm. Sweet maize is produced for different purposes. Each mode of its utilization, beside the yield and softness of the pericarp, has its specific requirements for certain quality. The taste (sweetness) and the ear appearance are the most important for sweet maize fresh market. Sweet maize that is transported needs to be of the uniform maturity in order to reduce the percentage of residues at mechanical harvest of the crop. Maintenance of sweetness after transport is also a very important trait. The shape and uniformity of the ear, the kernel color structure and taste are very important in selection of hybrids for the commercial production. Commercial processing (tinning or freezing) requires the uniform size and shape of the ear. The kernel structure, shape, size and fulfillment after cutting are requirements for several modes of utilization (processing) of sweet maize.Kukuruz šećerac se koristi za ljudsku ishranu u mlečnoj fazi razvoja endosperma, kada je zrno nežno, sočno i slatko. Najveći broj komercijalnih hibrida kukuruza šećerca se zasniva na jednom ili više recesivnih alela koji menjaju ugljenohidratni sastav endosperma. Kukuruz šećerac se proizvodi za različite načine korišćenja. Svaki način iskorišćavanja šećerca, pored prinosa i nežnosti perikarpa, ima specifične zahteve za određenim kvalitetom. Ukus (slatkoća) i izgled klipa su na prvom mestu po važnosti za potrošnju šećerca u svežem stanju. Šećerac koji se transportuje na velika rastojanja treba da ima uniformno stasavanje (sazrevanje) klipova da bi se redukovao procenat otpadaka u mehaničkoj berbi useva. Zadržavanje slatkoće posle transporta je takođe veoma važna osobina. Oblik i ujednačenost klipa, boja zrna, građa i ukus su veoma važni kod izbora hibrida za komercijalnu proizvodnju. Komercijalna prerada (konzerviranje ili zamrzavanje) zahteva ujednačenu veličinu i oblik klipa. Građa zrna, oblik, veličina i ispunjenost zrna posle rezanja su zahtevi za više načina iskorišćavanja (prerade) šećerca

Genetičke korelacije za važnija agronomska svojstva između S1 i HS familija u dva kompozita kukuruza (Zea mays L.)

Genetic correlations for more important agronomic traits between S1 and HS families of two composites of maize (Composite B and M) were investigated. For the grain yield genotypic correlation between S1 and HS families in Comp. B was significant, medium strong (0,359*), but too low for predictable purposes. Greater correlation for the grain yield was obtained in Comp. M, it was strong and highly significant (0,663**). Correlations for grain yield were lower than for the other investigated traits in both composites. For the ear height and 1000 kernel weight these correlations were higher in Comp. B, while for the rest of the traits they were greater in Comp. M, indicating greater share of the additive in the total genotypic variance in this composite. As far as the grain yield is concerned, combined S1-HS selection should be applied only in the Comp. M, based on the strong, highly significant correlation between investigated families. In Comp. B this is not the case. For this composite, alternative procedure, for the simultaneous improvement of the population per se and its combining ability, is first to apply S1, and after that HS selection, but with very low intensity (about 30%).U radu su proučavane genetičke korelacije važnijih agronomskih svojstava između S1 i HS familija u dva kompozita kukuruza (Kotnp. B i M). Za prinos zrna, genetička korelacija S1 i HS familija u Kotnp. B bila je značajna, srednje jaka (0,359*), ali i suviše niska da bi se sa sigurnošću, na osnovu prinosa S1 familije, sudilo o njenoj KS, ili obrnuto. Veća korelacija za prinos zrna utvrđena je u Komp. M i bila je jaka i visoko značajna (0.663**). Korelacije za prinos zrna bile su niže nego za druge ispitivane osobine u oba kompozita. Za visinu klipa i masu 1000zrna vrednosti ovih korelacija bile su veće u Komp. B, a za sve ostale osobine u Komp. M, pa je verovatno u Kompozitu M udeo aditivne u ukupnoj genetičkoj varijansi veći za većinu ispitivanih svojstava. Što se tiče prinosa zrna, kombinovana S1-HS selekcija bi se smela primeniti samo u Komp. M, na osnovu visoko značajne korelacije za ovu osobinu između ispitivanih tipova familija. U Komp. B ovo ne bi smelo da se uradi. Ovde je alternativa, za istovremenu popravku prinosa populacije per se i njene KS, naizmenična primena S1 i HS selekcije (najpre S1 a zatim HS), ali uz vrlo nizak intenzitet (oko 30%)