Effect of Within-Row Spacing on Agronomic and Morphological Characteristics of the Flue-Cured Tobacco Cultivars

In flue-cured tobacco (Nicotiana tabacum L.) production the aim is improvement of yield and quality (usability) of cured leaf. This has been achieved through development of new cultivars and adjustment of cultural practices. In Croatia, most of the flue-cured tobacco is grown at plant spacing of 45 cm within and 100 cm between rows, i.e. at planting density of about 22,000 plants per ha. In order to evaluate the effect of decreased planting density on agronomic and morphological characteristics of flue-cured tobacco, field experiments with six flue-cured tobacco cultivars and two within row plant spacings (45 and 55 cm) were conducted at two locations in the main Croatian flue-cured tobacco growing regions, over four years (2005 to 2008). Wider spacing within rows resulted in 396.12 kg ha-1 higher yield and 861.01 $ ha-1 higher value than the closer spacing. Change in price was not significant. Length, width, and leaf area of the 9th leaf also increased significantly at 55 cm within row spacing, while plant height and leaf number were unchanged. Cultivar x plant spacing and environment x plant spacing interactions were not significant for the studied traits. Results indicate that higher yield, higher value and good quality of cured tobacco leaf could be produced at 55 cm within row spacing (about 18,000 plants per ha)

Stalk rot resistance in Maksimir 3 synthetic maize population after four cycles of recurrent selection

Fusarium stalk rot (FSR) and anthracnose stalk rot (ASR), caused by Fusarium spp. and Colletotrichum graminicola (Ces.) G.W. Wils. respectively, are the two most important stalk diseases in maize which increase the incidence of stalk lodging and reduce grain yield. The aim of the present study was to (1) evaluate the effect of four cycles of recurrent selection in the Maksimir 3 Synthetic (M3S) maize population on ASR and FSR resistance and (2) to investigate the correlation among the different disease rating methods. The experiment included six M3S cycle populations per se and their test-crosses with a single cross hybrid. ASR resistance was estimated on artificially inoculated plant rows using three ratings (the number of infected internodes, the number of internodes rotten more than 75% and evaluation of outer stalk discoloration) whereas FSR resistance was estimated in artificially inoculated rows as well as in naturally inoculated rows by rating severity of disease symptoms on longitudinally cut stalks using the standard resistance scale. The results of the present study showed that four cycles of selection in the M3S maize population, conducted primarily for grain yield improvement, did not significantly affect its resistance to both ASR and FSR. Among the disease ratings a moderate positive correlation was found only between two ASR resistance ratings (the number of infected internodes and the number of internodes rotted more than 75%) in both population per se (r=0.49**) and population test-crosses (r=0.56**)

GROWING TOBACCO SEEDLINGS ON DIFFERENT FLOAT NUTRIENT SOLUTIONS

Rasad virdžinijskih duhanskih hibrida DH16 i DH17 je uzgojen na tri hranidbene otopine i posađen u poljskom pokusu u Kutjevu i Virovitici 2000. i 2001. godine. Pokus je izveden po randomiziranom potpunom blok rasporedu u 4 ponavljanja i sa 4 reda po 22 biljke na pokusnoj parcelici. Srednja dva reda, bez rubnih biljaka (40 biljaka) su korištena za procjenu prinosa, cijene i vrijednosti duhanskog lista nakon berbe i sušenja. Preporučene koncentracije hranjiva u hranjivoj otopini kod nas u proizvodnji su N:P:K= 150:75:150 ppm. U pokusu su korištene koncentracije N 150 i 170, P2O5 75 i 150, te K2O 150 ppm. Analize za sva svojstva rezultirale su značajnim razlikama u okolinama (lokacija x godina), dok je za cijenu i vrijednost signifikantna bila interakcija hibrid x okolina. Obzirom na sortiment, hibrid DH17 je u prosjeku imao nešto bolja gospodarska svojstva od hibrida DH16. Izvor hranjiva u otopini, kao niti njihova koncentracija nisu značajno utjecali na istraživana svojstva duhana. Stoga rezultati upućuju na mogućnost korištenja izvora hranjiva i njihove koncentracije u hranjivoj otopini korištenoj u pokusu za uzgoj rasada hibrida duhana DH16 i DH17.Seedlings of flue cured tobacco hybrid DH16 and DH17 grown in float system on three nutrient solutions were transplanted in a field experiment at two locations in 2000 and 2001. The experiment was organized as RCBD with four replicates and four 22 plant rows per each experimental plot. Middle two rows (40 plants) were used for analyzing yield, price and value. Recommended nutrient concentration for float system in Croatia is N:P:K = 150:75:150 ppm. In the experiment concentration of N was 150 and 170, of P2O5 75 and 150, and of K2O 150 ppm. The obtained data analyses resulted in significant differences between environments (year x location) for all the traits, while hybrid x environment interaction was significant for price and value. Hybrid DH17 was on the average slightly better than DH16 in all the traits. Source of nutrients and nutrient concentration did not have significant effect on the tobacco traits. The obtained results have indicated that the fertilizers and the nutrient concentration applied in the experiment can be used in the commercial tobacco production of the hybrids DH16 and DH17

Heritability of Indirect Bread-making Quality Traits in Segregating Generations of Two Winter Wheat Crosses

Modern wheat breeding programs aim to create cultivars with high genetic potential for yield and bread-making quality. The effectiveness of selection in segregating generations depends on the heritability of the traits under selection and on the correlations among traits. The aim of this study was to compare realized heritability of 1000 kernel weight and five indirect bread-making quality traits (grain protein content, wet gluten content, gluten index, the Zeleny sedimentation value and Pelshenke value) between segregating generations (F4 to F6) of two bi-parental wheat crosses, calculated using four different methods, and to estimate phenotypic correlations among these traits. Realized heritability of investigated traits, estimated as parent-off spring regression, ranged from 0.21 to 0.79. Realized heritability for wet gluten content, gluten index and Pelshenke value was much higher in comparison with other quality traits. Correlations between the four methods used to calculate realized heritability revealed the best agreement between heritability estimated as parent-off spring regression and that based on divergent screening, and the lowest agreement between realized heritabilities based on upward and downward screening. Strong positive correlations were observed among grain protein content, wet gluten content, and Zeleny sedimentation value; and strong negative correlations between gluten index on one side and grain protein content and wet gluten content on the other side

EFFECT OF NITROGEN FERTILIZATION ON GRAIN YIELD AND QUALITY OF HULLED AND HULLESS SPRING OATS

Na pokusnome polju Bc Instituta d.d. u Botincu postavljen je 2014. pokus s ciljem da se ispita utjecaj četiri razine gnojidbe dušikom na prinos i kvalitetu zobi. U pokusu je bilo uključeno osam genotipova zobi pljevičastog i dva genotipa zobi gologa zrna. Između razina gnojidbe dušikom kod genotipova pljevičastog zrna uočene su signifikantne razlike u prinosu, hektolitarskoj masi, masi 1000 zrna i visini biljke. Genotipovi zobi pljevičastog zrna razlikovali su se u svim proučavanim svojstvima. Interakcija genotip × gnojidba nije pronađena. Kod genotipova zobi gologa zrna pronađene su razlike u visini prinosa, hektolitarskoj masi i masi 1000 zrna, dok su se gnojidbe razlikovale samo u prinosu. Reakcija genotipova na povišenu razinu dušika bila je pozitivna. Porast prinosa kod genotipova pljevičastog zrna ostvaren pri gnojidbama većim od 124 kg/ha N nije bio signifikantan, dok su kod genotipova zobi gologa zrna gnojidbe sa 133 i 151 kg/ha N rezultirale najvišim prinosima. Kod genotipova zobi pljevičastog zrna, razlike u hektolitarskoj masi zrna između gnojidbi s povećanim razinama gnojidbe dušikom nisu bile signifikantne, dok kodgenotipova zobi gologa razlika između svih gnojidbi u hektolitarskoj masi zrna nije uočena.A field trial was set up in 2014 the growing season at the Bc Institute’s experimental field in Botinec aiming to investigate the effect of four levels of nitrogen fertilization on grain yield, test weight, thousand kernel weight and plant height of eight hulled and two hulless oat genotypes. Significant differences were found out among nitrogen fertilization levels as well as among the eight hulled genotypes for all traits. The interaction genotype × N fertilization was not significant. Significant differences among the hulless oat genotypes were found out for yield, test weight and thousand kernel weight, while the nitrogen fertilization levels differed only for yield. All genotypes reacted positively to the increased levels of nitrogen fertilization. The yield increase of hulled oat genotypes was not significant at nitrogen fertilization being higher than 124 kg/ha N. However, fertilization levels of 133 and 151 kg/ha N resulted in significantly higher yields for the two hulless oat genotypes. At the fertilization levels higher than 124 kg/ha N, differences in grain test weight were nonsignificant for hulled oat genotypes, while for the two hulless genotypes they were nonsignificant among all four nitrogen fertilization treatments

Evaluation of nitrogen use efficiency in the Maksimir 3 Synthetic maize population

Nitrogen use efficiency (NUE) has become an important trait for sustainable agriculture. Traits present in maize (Zea mays L) landraces that contribute to adaptation in nitrogen-limited environments are not easily implemented directly into modern maize breeding programs. Thus, the landraces might be improved by recurrent selection and afterwards used as source of certain traits for elite breeding material. The Maksimir 3 Synthetic (M3S) maize popu¬lation was created from landraces traditionally grown under low levels of soil fertility. The synthetic was subjected to recurrent selection for yield during three cycles and for improved NUE in the fourth cycle. In order to determine the effect of four cycles of recurrent selection, performance of populations per se (S0), population testcrosses, and populations per se selfed (S1) were evaluated in field trials under high and low nitrogen input conditions at four lo¬cations during 2010. The S0 populations had significantly higher grain yield (+20.6%), ear diameter (+2.6%), 1000 kernel weight (+3.3%) and ear leaf chlorophyll content (+31.2%) at the high nitrogen fertilization rate as compared to the low nitrogen fertilization rate. The S1 populations and testcross populations responded similarly to nitrogen fertilization. Genotype x nitrogen interaction for yield was not significant, but indication of specific adaptation to the nitrogen deficient environments was found. After the fourth cycle of recurrent selection, a significant increase in grain yield was found at both levels of nitrogen fertilization

Evaluation of Inoculation Methods for Determination of Winter Wheat Resistance to Fusarium Head Blight

One of the most severe winter wheat (Triticum aestivum L.) diseases is Fusarium head blight (FHB). It is believed that selection for resistance to FHB is better in high disease pressure environments, for which various methods of artificial inoculation are used. The standard spray method of artificial inoculation is believed to be technically demanding and labour intensive. Therefore, scattering Fusarium-infected maize stalks onto trial plots after wheat emergence is suggested as a suitable alternative. The aim of this study was to compare the mean values and heritability of the visual rating index (VRI) and the percentage of Fusarium-damaged kernels (FDK) between the two abovementioned methods of artificial inoculation and natural infection, and to determine the phenotypic correlations between the three methods for the studied traits. The achieved levels of VRI and FDK were comparable for the two methods of artificial inoculation and considerably lower under natural conditions. Heritability for VRI ranged over four years from 0.68 to 0.91 for the spray method, from 0.73 to 0.95 for the infected maize stalks, and from 0.26 to 0.65 for natural infection, whereas for FDK it ranged from 0.56 to 0.85, 0.38 to 0.83, and 0.11 to 0.44 for the three inoculation methods, respectively. The strong positive correlation between the two applied methods of artificial inoculation for studied traits suggests that scattering infected maize stalks could serve as a reliable supplement for the technically and labor-intensive spray method of artificial inoculation

Bc MANDICA–A NEW Bc WINTER WHEAT VARIETY

Bc Institut d.d. iz Zagreba u svoj proizvodni program uključio je novu visokorodnu sortu ozime pšenice pod imenom Bc Mandica. Sorta botanički pripada vrsti Triticum aestivum L. emend Fiori et Paol., ima bijeli glatki klas bez osja, zrno crvene boje te spada u varijetet Lutscens Al. Tijekom provedenih istraživanja u svrhu priznavanja prosječni urod novopriznate sorte u službenim pokusima Hrvatskog centra za poljoprivredu, hranu i selo – Zavoda za sjemenarstvo i rasadničarstvo iznosio je 8.438 kg/ha i nadmašio je sve standardne pšenice, Srpanjku, Žitarku i Divanu. Nakon uspješno provedenoga ispitivanja, 2014. godine upisana je na Sortnu listu Republike Hrvatske. Sorta Bc Mandica pripada grupi srednje ranih sorti, ostvaruje stabilan i izuzetno visok urod zrna, a po pokazateljima kvalitete zrna, brašna i tijesta, sorta Bc Mandica svrstana je u B1 grupu kvalitete.In 2014 a new winter wheat variety developed by the Bc Institute, Bc Mandica, was released. Bc Mandica belongs to species Triticum aestivum L. emend Fiori et Paol. var. Lutescens Al, it has white awnless ears and red grains. Average yield of the Bc Mandica in official trials conducted by the Croatian Centre for Agriculture, Food and Rural Affairs - Institute for Seed and Seedlings was 8.438 kg/ha and, it outyielded all three standard winter wheat varieties Srpanjka, Žitarka and Divana. After successful registration procedure, Bc Mandica was enlisted to the List of Varieties of the Republic of Croatia in 2014. In regard to the growth season Bc Mandica could be classified as middle early. It achieves stabile and exceptionally high yield and, according to quality parameters of grain, flower and dough, it belongs to the B1 quality group

Genetic Variability of Tocol Content in a Genebank Collection of Temperate Maize Inbred Lines from Southeastern Europe

Maize is considered a promising candidate for biofortification through breeding, given its widespread cultivation and significance as a food crop. This cost-effective and sustainable approach could be used to increase the content of different tocol compounds, i.e., vitamin E, in maize grain due to the well-documented genetic variability. In the present study, an evaluation of the content of nine different tocol traits was performed in a genebank collection of 88 inbred lines of temperate maize grown at two locations in Croatia in 2019. A large genotypic variability within the studied material was observed for α-tocopherol, γ-tocopherol, δ-tocopherol, total tocopherols, α-/γ-tocopherol ratio, α-tocotrienol, γ-tocotrienol, total tocotrienols and total tocols with corresponding coefficients of variation of 52, 61, 51, 45, 106, 24, 54, 33 and 38%, respectively. Heritability estimates ranged from 0.66 for α-tocotrienol to 0.95 for γ-tocopherol. The content of α-tocopherol, which has the highest vitamin E activity and is therefore most interesting for selection, was not significantly correlated with either grain color or grain type. Comparison of the effects of simulated selection with an intensity of 20% on increased α-tocopherol content using the two selection criteria, absolute α-tocopherol content and α-/γ-tocopherol ratio, showed that the highest absolute α-tocopherol content was a better selection criterion. Indeed, simulated selection based on the absolute α-tocopherol content resulted in a 64% increase in this compound without significantly affecting the total tocopherols, the total tocotrienols, and the α-/γ-tocopherol ratio