Özden Öztürk

STUDIES ON DIFFERENTIAL RESPONSE OF SPRING CANOLA CULTIVARS TO BORON TOXICITY

Although many states recommend boron (B) fertilizer for many field crops, information about B toxicity of canola is lacking. This experiment was carried out at Central Anatolia, Turkey from 2002 to 2003, to determine genotypic range in B efficiency of eight spring canola cultivars, to identify the B-inefficient cultivars and to identify specific responses. The cultivars were grown under B moderate deficiency (extractable B 0.56 mg kg−1) and toxic B applied (15 kg B ha−1) conditions. According to the results, seed yield varied significantly among the cultivars and B application decreased the seed yield by 31% on average. Also, toxic B application reduced protein and oil contents similar to seed yield, and increased leaf B concentration in all varieties. This study has shown that leaf B concentration has increased considerably when B is applied to Pactol and Star cultivars, but seed yield of +B and −B has not shown significantly a change. It is possible to say that Star and Pactol—which have not been affected by the toxic B application—are genotypes that are tolerant to B toxicity and may be cultivated at B toxic lands.

Micronutrient contents in leaves of sunflower cultivars grown with different boron doses.

SUMMARY Although boron is essential for crop growth, the amount required differs among plant species. Sunflower (Helianthus annuus L.) requires greater quantities of boron to satisfy its metabolic needs than other cultivated species. The present work was undertaken to evaluate what effects five boron doses of 0, 2.5, 5.0, 7.5 and 10.0 kg B ha-1 (applied as a spray of boric acid, H3BO3) would have on micronutrient contents in leaves of four sunflower cultivars grown in B-deficient calcareous soils (0.19 B mg kg-1) during the 2001 growing season. Boron (B), iron (Fe), manganese (Mn), zinc (Zn) and copper (Cu) concentrations were measured in sunflower leaves at the flowering stage. According to the results, the B concentration in the leaves was highly correlated with boron doses, that is, the leaf B content increased in accordance with increasing B doses applied to the soil. Fe, Mn, Cu, and Zn concentrations in the leaves were not changed by the different B levels. However, leaf Mn, B and Cu concentrations varied with the cultivars. Among the cultivars, TR-4098 had the highest Mn (90.74 mg kg-1) and Cu contents (45.95 mg kg-1), while AS-615 had the highest B (83.52 mg kg-1) and Fe (202.55 mg kg-1) concentrations.

Effects of boron application on morphine yield of some varieties of poppy (Papaver somniferum L.)

Poppy is placed among the most important medicinal plants in Turkey. The present study was carried out to determine the effect of different boron doses on morphine yield of four poppy cultivars grown in the Western Anatolia Region of Turkey during 2002–2003 growing season. The field experiment was set up in a “Factorial in Randomized Complete Block” design with four replications, the varieties (Ankara 94, Kocatepe 96, Afyon Kalesi 95 and Karahisar 96) were assigned to the main plots and five boron doses of 0, 1, 3, 9 and 36 kg B ha−1 (as spray of boric acid) were assigned to the subplots. The results revealed that the effect of boron doses on capsule yield and morphine yield were significant but their effect on morphine ratio was insignificant. The highest capsule yield (1011.6 kg ha−1) and morphine yield (5.96 kg ha−1) was obtained by the application of 1 kg B ha−1 and values showed a decreasing trend at higher boron doses. The highest dose of boron applications (36 kg ha−1) produced the lowest values for capsule yield (376.4 kg ha−1) and morphine yield (2.05 kg ha−1). Among the cultivars, Karahisar 96 had highest capsule yield, morphine ratio and morphine yield (863.6 kg ha−1, 0.65%, 5.64 kg ha−1, respectively). Our results suggest that 1 kg ha−1 boron application would be sufficient to obtain good morphine yield.