Analiza predkomisijskih pokusa kukuruza i germplazme razvijene u oplemenjivačkoj stanici u Altınovi od 2015. do 2018. godine

Main goal of the most breeding programs is to develop highly adaptive hybrids in various environments, and the most important limitation are complex interactions between genotype, environment and management. Every hybrid breeding program follows certain strategy for new hybrid development. One possible strategy is to develop hybrids with lower adaptability, achieving best performance in “high input” environments (breeding for “race-horses”). However, another approach is to breed for hybrids with higher adaptability and stable performance across a wide range of environments (breeding for “work-horses”). High stability needs to be accompanied by high yield performance to insure profits, so stability should be monitored along with performance in breeding trials. Aim of this research was to analyze the new germplasm developments and their performances in the pre-registration trials in Turkey by the means of BLUP and GGE models. Heritability estimates for grain yield ranged from 0.58 to 0.85, and relative stability of all hybrids and checks is detected across all years. Cause of the high estimates of G×L interaction were crossovers of genotype performances across locations. The location Altinova was the least stable location across years. One hybrid was selected as a future check based on stability parameters across environments. As G×E interaction remains the greatest challenge in modern maize breeding, more research is needed in this field. Therefore mixed-model based approach is a valuable tool for analysis of genotype performances in maize breeding trials.Glavni cilj komercijalnih oplemenjivačkih programa na kukuruzu je razviti hibride visoke prilagodljivosti u raznim okolinama, pri čemu glavno ograničenje predstavljaju kompleksne interakcije između genotipa, okoline i upravljanja. Svaki oplemenjivački program slijedi određenu strategiju za stvaranje hibrida. Jedna od strategija je stvaranje hibrida koji nemaju vrhunsku adaptabilnost, ali mogu postići najviše prinose u visokoprinosnim okolinama („trkaći konji“), dok je druga strategija stvaranje hibrida visoke adaptabilnosti u raznim okolinama („radni konji“). Visoka stabilnost mora biti popraćena visokim prinosima kako bi se osugurao profit, stoga bi se u oplemenjivačkim pokusima stabilnost trebala pratiti zajedno s prinosom. Cilj ovoga istraživanja je analiza nove germplazme (inbred linija i hibrida) kroz predkomisijske pokuse na raznim lokacijama u Turskoj, korištenjem BLUP i GGE metoda za predviđanje, odnosno stabilnost prinosa. Heritabilnost za prinos zrna iznosila je od 0.58 do 0.85, a relativna stabilnost svih hibrida i standarda je zabilježena u svim godinama. Uzrok visokih vrijednosti G×L interakcije su različite vrijednosti genotipova kroz lokacije. Lokacija Altınova bila je najmanje stabilna kroz sve četiri godine. Jedan hybrid je izabran kao budući standard na osnovu stabilnosti u svim okolinama. Kako G×E interakcija i dalje predstavlja najveći izazov u modernom oplemenjivanju kukuruza, potrebno je još istraživanja u tome području, a korištenje mješovitih modela predstavlja vrijedan alat za analizu genotipova u oplemenjivačkim pokusima

ODNOSI IZMEĐU SVOJSTAVA OTPORNOSTI NA KUKURUZNU ZLATICU I KONCENTRACIJE ELEMENATA U KORIJENU U GERMPLAZMI KUKURUZA

Western corn rootworm – WCR (Diabrotica virgifera virgifera LeConte) is an important maize pest in Croatia. Using native resistance of maize germplasm could reduce chemical treatments and other costs in maize production. Objectives of this study were: i) to assess variability of WCR resistance traits (root injury, regrowth and size) and concentrations of nine elements in roots of 128 maize genotypes, and ii) to determine correlations among the traits and ion concentrations. Results revealed high variability of maize genotypes for both WCR resistance traits and ion concentrations. Significant moderate negative correlations (>-0.4) were detected between root injury and boron as well as between root regrowth and iron, manganese and zinc concentrations in root. Consequently, ion concentration in maize roots might have an impact on WCR resistance research.Kukuruzna zlatica (Diabrotica virgifera virgifera LeConte) važan je štetnik kukuruza u Hrvatskoj. Korištenje prirodne otpornosti u germplazmi kukuruza moglo bi smanjiti troškove kemijskoga tretiranja, kao i ostale troškove pri proizvodnji kukuruza. Glavni ciljevi ovoga rada bili su: i) procijeniti varijabilnost svojstava otpornosti na kukuruznu zlaticu (oštećenje, sekundarni porast i veličina korijena) i koncentracije devet elemenata u korijenu 128 genotipova kukuruza te ii) utvrditi korelacije između svojstava otpornosti i koncentracije iona. Rezultati su pokazali veliku varijabilnost ispitivanih genotipova i za svojstva otpornosti na kukuruznu zlaticu i za koncentracije iona u korijenu. Značajne negativne korelacije (>-0.4) utvrđene su između oštećenja korijena i bora, kao i između sekundarnoga porasta i željeza, mangana i cinka. Koncentracija iona u korijenu kukuruza mogla bi imati veći utjecaj u istraživanju otpornosti kukuruza na kukuruznu zlaticu

Chlorophyll fluorescence analysis of photosynthetic performance in seven maize inbred lines under water-limited conditions

Background and Purpose: Photosynthetic efficiency in crops can be associated with stress resistance and yield increase. In maize, photosynthetic efficiency is important in inbred lines during breeding process and in seed production, as well as in hybrids. Objective of this study is to determine differences in photosynthetic efficiency under the water-limited conditions between seven flint and dent maize inbred lines belonging to various heterotic groups. Moreover, this investigation will serve as a preliminary study for the QTL analysis of chlorophyll fluorescence parameters in order to understand the genetic and physiological background to drought stress tolerance in maize. Materials and Method: Photosynthetic efficiency was measured in maize field nursery in Osijek during silking by Hansatech Handy-PEA analyzer in the elite inbreds Os1767/99, Os1252/99, Os163_9, B73, Mo17, Os6_2 i B84. The data obtained were used to calculate two biophysical parameters that describe the photochemistry of PSII: maximum quantum yield of photosystem II (Fv/Fm) and performance index on absorption basis (PIABS). Obtained data were subjected to statistical analysis applying least significant difference (LSD) and cluster analysis. Results and Conclusions: Differences in photosynthetic efficiency appeared to be higher within dent inbred lines than between dents and flints. Although investigated parameters of chlorophyll fluorescence (Fv/Fm and PIABS) revealed similar clustering of inbred lines, there was slight difference concerning the grouping of the line Os6_2. Therefore we recommend the combined use of these two main parameters of chlorophyll fluorescence when the investigation includes photosynthetic performance in stress challenged plants, such as water-limited conditions

UTJECAJ GUSTOĆE SJETVE NA AGRONOMSKA SVOJSTVA I FOTOSINTETSKU UČINKOVITOST IBM POPULACIJE KUKURUZA

Photosynthesis is a vital process in plant physiology. Performance index is an indicator of plant vitality and is used as a main parameter in chlorophyll fluorescence measurements. Plant density is an important factor in maize production that can affect grain yield. Objective of this paper was to estimate the effect of plant density on agronomic traits and photosynthetic efficiency in the maize IBM population. The results showed a decrease in grain yield per plant basis (20 plants per plot) in higher plant density (normal density - 3.88 kg per plot, high density - 2.95 kg per plot) and an increase in grain yield per unit area (yield/ha) in higher plant density (normal density - 11.03t ha-1, high density - 13.64 t ha-1). Performance index was decreased in higher plant density (normal density - 5.31, high density - 4.95). Statistical analysis showed highly significant effect (p<0.001) of density on performance index and highly significant effects (p<0.001) of plant density and genotype on maize yield. Low positive correlation was observed between grain yield per plot and performance index (r = 0.36, p<0.001).Fotosinteza je vitalni dio biljne fiziologije. Indeks fotosintetske učinkovitosti (eng. performance index) indikator je vitalnosti biljke i koristi se kao glavni parametar u mjerenju fluorescencije klorofila. Gustoća sklopa važan je faktor proizvodnje kukuruza, koji može utjecati na prinos zrna. Cilj ovoga istraživanja bio je procijeniti utjecaj gustoće sklopa na agronomska svojstva i fotosintetsku učinkovitost kod IBM populacije kukuruza. Rezultati su pokazali smanjenje prinosa zrna na osnovijedne biljke (20 biljaka po parceli) u gušćem sklopu (manja gustoća sklopa - 3,88 kg po parceli, veća gustoća sklopa - 2,95 kg po parceli) i povećanje u prinosu zrna na osnovi prinosa po jedinici površine (prinos/ha) u gušćem sklopu (manja gustoća sklopa - 11,031 ha-1, veća gustoća sklopa 13,641 ha-1). Indeks fotosintetske učinkovitosti smanjio se s povećanjem gustoće sklopa (manja gustoća sklopa - 5,31, veća gustoća sklopa 4,95). Statističkom analizom utvrđen je značajan utjecaj (p<0,001) gustoće sklopa na indeks učinkovitosti fotosinteze i statistički značajni utjecaji (p<0,001) gustoće sklopa i genotipa na prinos zrna. Uočena je slaba pozitivna korelacija između prinosa zrna po parceli i indeksa učinkovitosti fotosinteze (r=0.36, p<0,001)

Uticaj specifičnosti vremenskih prilika u Hrvatskoj 2010. i 2011. na prinos kukuruza

Kukuruz je glavna ratarska kultura na oranicama Hrvatske. Prema podacima Državnog zavoda za statistiku (Statistički ljetopis 2011) u dekadnom periodu 2001.-2010. kukuruz je u Hrvatskoj uzgajan  prosječno na 303300 ha godišnje uz velika variranja ostvarenog prinosa zrna po godinama u rasponu od 4,2 do 8,0 t/ha. Vremenske prilike, prvenstveno količina i raspored oborina, te prosječne temperature zraka, glavni su razlozi ovakvih razlika prosječnih prinosa kukuruza. Cilj ovoga rada je analizirati oborinski i temperaturni režim tokom vegetacije kukuruza 2010. i 2011. u šest gradova kontinentalne Hrvatske (Osijek, Slavonski Brod, Bjelovar, Sisak, Zagreb i Varaždin) sa stajališta pogodnosti za uzgoj kukuruza. Godina 2010. bila je uglavnom povoljna za uzgoj kukuruza i te je godine ostvaren u Hrvatskoj prosječan prinos 7,0 t/ha. Količina oborina u periodu  april-septembar (prosjek šest gradova)  iznosila je 710 mm ili 54% iznad višegodišnjeg prosjeka, dok su temperature zraka u istom periodu bile 17,9 oC ili  veće za 1.0 oC. Za razliku od 2010. godina 2011. bila je nepovoljna za uzgoj kukuruza zbog suše i visokih temperatura zraka. Tako je u promatranih šest gradova prosječna količina oborina bila  274 mm ili  oko 40% ispod višegodišnjeg prosjeka, dok je temperatura zraka bila 19,2 oCiliza 2,3 oC iznad prosjeka. Kao posljedica nepovoljnih vremenskih prilika  procjena je da su prinosi kukuruza u Hrvatskoj u 2011.  i do 30% niži nego u normalnim godinama. Odgovarajućom agrotehnikom (konvencionalna umjesto reducirane obrade tla, oranje u jesen umjesto u proljeće uz zaoravanje većih količina gnojiva, osobito kalija) te uzgojem otpornijih hibrida na sušu, mogu se ublažiti posljedice suše za kukuruz

REAKCIJA KUKURUZA I JEČMA NA KALCIZACIJU FERTDOLOMITOM

Aim of this study was testing of maize and barley response to Fertdolomite (24.0% CaO + 16.0% MgO + 3.0% N + 2.5% P2O5 + 3.0% K20) application (crop rotation: maize 2008 - barley 2009 - maize 2010). Grain yield was increased by 12% (maize 2010) and 22% (barley). Mean concentrations 0.347% P, 2.44% K, 0.492% Ca and 0.176% Mg (leaves), 0.294% P, 0.334% K, 0.006% Ca and 0.093% Mg (grain) were found and due to Fertdolomite they were increased by 12% (P), 8% (K) and 19% (Ca) in leaves and by 14% (P) in grain.Cilj ovoga rada bio je istraživanje reakcije kukuruza i ječma na primjenu Fertdolomita (24,0% CaO + 16,0% MgO + 3,0% N + 2,5% P205 + 3,0% K2O) u stacionarnome poljskome pokusu (plodored: kukuruz 2008. - jari ječam 2009. - kukuruz 2010). Prinos kukuruza u 2010. povećan je za 12%, a ječma za 22%. Prosječne koncentracije u kukuruzu 2010. godine bile su 0,347% P, 2,44% K, 0,492% Ca i 0,176% Mg (listovi), 0,294% P, 0,334% K, 0,006% Ca i 0,093% Mg (zrno, a uslijed Fertdolomita povećane su za 12% (P), 8% (K) i 19% (Ca) u listu i za 14% (P) u zrnu

Comparative Morphology of Incisor Enamel and Dentin in Humans and Fat Dormice (Glis glis)

The structure of teeth in all living beings is genetically predetermined, although it can change under external physiological and pathological factors. The author’s hypothesis was to indicate evolutional shifts resulting from genetic, functional and other differences. A comparative study about certain characteristics of incisors in humans and myomorpha, the fat dormouse (Glis glis) being their representative as well, comprised measurements of enamel and dentin thickness in individual incisor segments, evaluation of external enamel index, and also assessment of histological structure of enamel and dentin. The study results involving dormice showed the enamel to be thicker in lower than in the upper teeth, quite contrary to enamel thickness in humans. In the upper incisors in dormice the enamel is the thickest in the medial layer of the crown, and in the cervical portion of the crown in the lower incisors. The thickness of dentin in dormice is greater in the oral than in the vestibular side. These findings significantly differ from those reported in reference literature, but they are based on the function of teeth in dormice. Histological characteristics of hard dental tissues in dormice are similar to those in humans, with exception of uniserial structure of enamel and appearance of dentinoenamel junction