Changes of physical and chemical characteristics of plum fruits during ripening

Autor: Dugalić, Krunoslav
Přispěvatelé: Čmelik, Zlatko
Jazyk: chorvatština
Rok vydání: 2015
Předmět:
Popis: U Republici Hrvatskoj šljiva zauzima treće mjesto po površinama i proizvodnji plodova. Sorte šljiva zastupljene u hrvatskim voćnjacima često su tržišno neatraktivne ili su osjetljive na virus šarke te je njihova proizvodnja nekonkurentna. Oplemenjivački program šljive u Njemačkoj stvorio je nekoliko novih sorata šljiva (´Topstar´, ´Toptaste´, ´Haganta´, ´Jojo´, ´Tophit´) koje su tolerantne na virus šarke, a odlikuju se boljim pomološkim, fizikalnim i kemijskim svojstvima. Agroekološki uvjeti značajno utječu na kakvoću plodova te je potrebno poznavati adaptibilnost novih njemačkih sorata na agroekološke uvjete istočne Hrvatske, gdje je veliki bazen uzgoja šljiva i gdje se šljiva tradicionalno uzgaja stoljećima. Pomološka, fizikalna i kemijska svojstva mogu značajno varirati u pojedinim područjima uzgoja, a s time je povezano i određivanje roka berbe za pojedine sorte. Neprikladan rok berbe razlog je propadanja velikoga postotka plodova u voćnjacima jer ne postoje univerzalni parametri za određivanje roka berbe. Cilj ove disertacije bio je prikazati gospodarsku evaluaciju novih sorata šljiva (´Topstar´, ´Toptaste´, ´Haganta´, ´Jojo´, ´Tophit´) u agroekološkim uvjetima istočne Hrvatske te utvrditi dinamiku promjena fizikalnih i kemijskih svojstava plodova tijekom zrenja i odrediti optimalni rok berbe u odnosu na klimatske čimbenike. Istraživanje je provedeno u pokusnome nasadu šljiva na pokušalištu Poljoprivrednoga instituta Osijek, objekt Tovljač – istočno od Osijeka. Pokusni nasad posađen je 2005. godine. U disertaciji je istraživano 6 sorata šljiva: ´Toptaste´, ´Haganta´, ´Jojo´, ´Topstar´, ´Tophit´ i ´Čačanska ljepotica´ cijepljenih na podlozi WaxWa. Razmak sadnje je 4 × 2,5 m. Uzgojni je oblik popravljena vretenasta piramida. Sorte su posađene u tri reda, gdje je svaki red predstavljao repeticiju. U svakom redu posađena su 4 stabla svake sorte koje predstavljaju blok. Blokovi su randomizirani. U pokusnome nasadu nije uveden sustav za navodnjavanje te su primijenjene standardne tehnološke mjere gnojidbe, njege i zaštite. Berba plodova bila je u 4 roka berbe počevši od trenutka promjene pokrovne boje ploda nastavljajući se u tri iduće berbe svakih 5 – 7 dana. Istraživanje je trajalo dvije godine. Mjerenja su obuhvatila praćenje klimatskih prilika, praćenje fenofaze cvatnje i dinamiku rasta ploda, rodnost i pomološke značajke sorata te promjene fizikalnih i kemijskih svojstava plodova tijekom faze zrenja. Razlike između sorata, rokova berbe i klimatskih čimbenika s obzirom na fizikalna i kemijska svojstva statistički su obrađene analizom varijance. Istraživanjem šećera u plodu šljive utvrđeno je da klimatske prilike značajno utječu na kakvoću ploda šljive. Tijekom zrenja, koje prati povećanje sume toplinskih jedinica (GDD vrijednosti), povećava se sadržaj: topljive i ukupne suhe tvari, saharoze, glukoze i ukupnih šećera, razvoj boje i antocijana. Pod utjecajem klimatskih prilika godine ustanovljene su razlike u svih sorata u sadržaju i stanju spomenutih svojstava ploda. U obje godine istraživanja istraživane su sorte postigle punu zrelost uz slične GDD vrijednosti. Tvrdoća ploda postupno se smanjivala tijekom zrenja u svih istraživanih sorata, a u vrijeme potpune zrelosti izmjerena je najmanja tvrdoća. U vrijeme potpune zriobe plodovi svih sorata u obje godine imaju gotovo istu tvrdoću. Boja kožice ploda postupno se sve više razvijala tijekom zrenja. Za vrijeme zrenja količina antocijana nije se pravilno povećavala, nego je oscilirala od roka do roka berbe, od sorte do sorte, pa nisu utvrđene određene pravilnosti. Pod utjecajem klimatskih prilika godine utvrđene su razlike u sadržaju polifenola i antioksidacijske aktivnosti. Više polifenola i veću antioksidacijsku aktivnost sadržavali su plodovi u toplijoj i sušnijoj 2012. negoli u 2013. godini. Ustanovljena su velika variranja između pojedinih rokova berbe. Tijekom zrenja vrijednost DA indeksa mijenjala se dosta promjenjivo i nije pokazala stabilnu pravilnost, pa između pojedinih rokova berbe nema opravdanih razlika. Za utvrđivanje optimalnoga roka berbe mogu se rabiti nedestruktivni kriteriji: boja i GDD, a od destruktivnih: tvrdoća ploda, topljiva suha tvar i ukupni šećeri. Sorte ´Toptaste´, ´Tophit´ i ´Haganta´ postižu visoku kakvoću plodova u agroekološkim uvjetima istočne Hrvatske. In Croatia, plums occupy the third place with respect to the total fruit plantation area and the volume of fruit production. The plum cultivars represented in Croatian orchards are often commercially unattractive or sensitive to the PPV and their production is not competitive. A plum breeding program in Germany has brought to development of several new cultivars of plums (´Topstar´, ´Toptaste´, ´Haganta´, ´Jojo´, ´Tophit´) that are tolerant to the plum pox virus and are characterized by more favourable pomological, physical and chemical properties. Environmental conditions significantly affect the quality of the fruit and it is necessary to study the adaptability of the new German cultivars to the eastern Croatian agroecological conditions where a large pool of plums has been traditionally cultivated for centuries. The pomological, physical and chemical properties of plums can vary significantly in different cultivation areas as can the subsequent determination of the harvesting period for certain cultivars. Inadequate harvest-time can cause deterioration (decay) of a high percentage of fruits in orchards. Unfortunately, there are no universal parameters which would govern determination of the harvest-time. The aim of this dissertation is to perform economic evaluation of new cultivars of plums (´Topstar´, ´Toptaste´, ´Haganta´, ´Jojo´, ´Tophit´) in the eastern Croatian environmental conditions and to investigate the dynamics of change of the physical and chemical properties of the fruit during ripening and harvesting in relation to climatic factors. The research was conducted in the experimental plum orchard of the Agricultural Institute Osijek, at location ’’Tovljač’’, situated east of Osijek. The experimental orchard was planted in 2005. The dissertation deals with six plum cultivars: ´Topstar´, ´Toptaste´, ´Haganta´, ´Jojo´, ´Tophit´ and ´Čačanska ljepotica´, grafted on a WaxWa rootstock. The planting density was 4 × 2.5 m. The growing form was a repaired spindle shape pyramid. The cultivars were planted in three rows, each row representing a replication. Each row included 4 trees of each cultivar, which then constituted a block. The blocks were randomized. There was no irrigation system in the experimental orchard and what was implemented are the standard technological measures of fertilization, care and protection. The harvest was divided in 4 harvesting periods and commenced after the fruit had changed its covering colouring. The other three harvesting sequences were organized every 5-7 days. The research was done within two years. The measurements included monitoring of the climate conditions, flowering stages, fruit growth dynamics, yield and the pomological characteristics of the changes on the cultivars regarding the physical and chemical properties of the fruit during the variance. The analysis of the sugar content in the plums has revealed that climate conditions have significant impact on the quality of fruit. During the ripening, which was accompanied with an increase in the heat sum (GDD), it came to a rise in the content of soluble and total solids, sucrose, glucose, total sugars, colour development and anthocyanins. Under the influence of climate conditions throughout the year, the established differences referred in all cultivars to both the content and the state of the aforementioned properties of the fruit. In both years of testing, the researched cultivars reached full maturity with more or less the same GDD values. With respect to all studied cultivars, the hardness of the fruit was gradually reduced during the ripening and at the time of full maturity, the minimum hardness was achieved. At the time of full ripening, the fruits of all the cultivars were characterized by almost the same hardness in both years. During the ripening, the colour of the fruit skin became progressively more developed whereas the quantity of anthocyanin was not regularly increased but it fluctuated with no particular regularity depending on a period of time and a cultivar. Under the influence of climate conditions throughout the year, there were some differences in the content of polyphenols and in the antioxidant activity. Comparing the two years, the fruit was featured by more polyphenols and a more intensive antioxidant activity in the warmer and drier 2012. Large variations were detected between certain harvest times. During the maturation, the value of the DA index was changing quite variably and did not show stable regularity while between certain harvest times, there were no significant differences. To determine suitable harvest-time, the following non-destructive and destructive criteria can be used: colour and GDD (non-destructive criteria), and fruit firmness, soluble solid substance and total sugars (destructive criteria). Cultivars ´Toptaste´, ´Tophit´ and ´Haganta´ can provide high fruit quality in the agroecological conditions of eastern Croatia.
Databáze: OpenAIRE
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