The variation of phytic and inorganic phosphorus in leaves and grain in maize populations

Abstract

The phytate function in plants is still not completely understood: it is the primary storage P form in seeds that is utilized during germination and early seedling development. Approaches to resolve problem of the bad nutritive quality of grain phytate include engineering of crops with reduced levels of seed phytic acid. The objective of this study was to investigate genetic variability and correlation of phytic (Pphy) and inorganic phosphorus (Pi) and soluble proteins among 28 maize populations, consisted into three groups: low-, intermediate- and high-phytic populations, with the aim to determine the potential of enhancing the P profile of maize plants and high grain yield through selection. The highest genetic variability of Pi and Pphy content in leaves was expressed in group with intermediate Pphy content in grain. Meanwhile, leaves of low-phytic populations were characterized with low Pphy, too (averagely 18%) and high content of soluble proteins (averagely 15%) in relation to high- and intermediate-phytic populations. Additionally, the lowest genetic variability of protein content was also noticeable in leaves of low-phytic populations. Positive correlation between Pi and protein content was observed in leaves of low- and high-phytic populations. The negative correlation between Pphy and Pi was detected in maize grain, but correlation was significant only in intermediate-phytic group. The highest, but not significant, average yield was observed in group of low-phytic populations, as well as its relative high genetic variability. That indicates that development of high yielding genotypes with lower phytate in grain is reasonable, and could be potentially useful in enhancing the sustainability and decreasing of environmental impact in agricultural production.

Uloga fitata u biljkama još nije potpuno razjašnjena: on predstavlja prevashodno skladišnu P formu u semenu, koja se koristi tokom klijanja i ranog rasta klijanaca. Antinutritivni kvalitet fitata iz zrna je inicirao rad na inženjeringu biljnih vrsta sa smanjenim nivoom fitinske kiseline u zrnu. Cilj ovog rada je da se ispita genetska varijabilnost i korelacije između fitinskog (Pphy) i neorganskog fosfora (Pi), kao i rastvorljivih proteina kod 28 populacija kukuruza, podeljenih u tri grupe: nisko, srednje i visoko fitinske, da bi se utvrdio potencijal poboljšanja P profila kod kukuruza, uz visok prinos preko selekcije. Najveća genetska varijabilnost Pi i Pphy je bila ispoljena u listovima kukuruza populacija sa srednjim nivoom fitata u zrnu. Međutim, nisko fitinske populacije su pored niskog sadržaja Pphy u listovima (prosečno za 18%) imale i viši nivo rastvorljivih proteina (prosečno za 15%), u odnosu na visoko i srednje fitinske populacije. Takođe, najniža genetska varijabilnost u sadržaju proteina je bila prisutna u listovima nisko fitinskih populacija. Pozitivna korelacija između Pi i proteina je bila uočena u listovima nisko i visoko fitinskih populacija. Negativna korelacija između Pphy i Pi je bila uočena u zrnu kukuruza, ali je bila značajna samo u grupi srednje fitinskih populacija. Najveći prosecan prinos, ali ne značajno, je bio prisutan kod nisko fitinskih populacija, uz najveću genetsku varijabilnost. Ovo ukazuje na mogućnost razvijanja visokoprinosnih genotipova sa niskim nivoom fitata u zrnu, što bi moglo biti potencijalno korisno sa aspekta održivosti i smanjenja uticaja okoline na poljoprivrednu proizvodnju.