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Carbon isotope discrimination (D) has been recognized as a valuable phenotyping tool in wheat breeding. However, technical expertise and analysis cost restrict its large-scale use. We examined the associations of ash content (AC), minerals content (Ca, K, Mg, Fe and Mn) and leaf chlorophyll content (Chl) with grain D and grain yield (GY) to assess their potential as substitute to grain D. We evaluated 49 wheat genotypes under two water deficit regimes (W 120 and W 200 ) in a rain-out shelter. Leaf chlorophyll content (Chl) was strongly correlated with grain D and GY under moderate water deficit regime (W 200 ). Significant and negative correlations (P \ 0.01) of AC and potassium concentration (K) with grain D, and between AC and GY was observed under both water regimes, while manganese concentration (Mn) was negatively correlated with grain D under W 120 regime only and magnesium concentration (Mg) correlated negatively under the W 200 regime only. Grain D was correlated (P \ 0.01) positively with photosynthesis rate (A), stomatal conductance (g s ) and GY, while correlated negatively (P \ 0.01) with intrinsic water use efficiency (iWUE) under both water regimes. Results confirm the role of grain D as an indirect selection criterion for drought tolerance under a wide range of drought conditions. Additionally, Chl is the most suitable trait to predict yield under moderate water deficit conditions. AC and K concentration in grain proved potentially useful and economical alternative criterion to grain D in the evaluation of differences in yield potential and drought tolerance in wheat under drought.

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Soil compaction is a global issue pertaining to agricultural lands. The frequent use of farm machinery and field operations at the same depth are the major causes of soil compaction. The gradual increase in soil compaction deteriorates maize grain quality due to reduced nitrogen (N) uptake. Quality food production by reducing soil compaction is the need of time, which can be achieved through deep tillage and N management. In this study, three tillage systems viz. conventional tillage (using cultivator), tillage with mould board plough +2-cultivations (MBP), and tillage with chisel plough +2-cultivations (CP); and three nitrogen levels viz. 100, 150 and 200 kg ha–1 were used to evaluate their effect on soil properties, N uptake and grain quality in maize. Lower bulk density (1.41 Mg m–3), higher total porosity (0.47 m3 m–3) and higher nitrogen uptake (96.01 kg ha–1) was recorded under chisel plough (CP) compared with other tillage systems. Different N levels had significant effect on grain and total N uptake and grain quality, while soil properties remains unaffected. Higher N uptake was recorded with 200 kg ha–1 N application than other treatments. Similarly, 8.51% and 8.57% more grain protein contents were recorded with 200 kg ha–1 N during first and second year respectively. Unlike grain protein, starch and oil contents were negatively affected by N application being higher starch (71.7%) and oil contents (3.41%) with less N supply (100 kg ha–1). However, interaction effect of tillage and nitrogen levels was found non-significant for all studied parameters except for oil contents. Higher oil contents were recorded with MBP along with 100 kg ha–1 N application. Overall study indicated that deep ploughing with CP is important for maize to explore more soil area for nutrient uptake and N is also important for improving grain quality especially protein contents an important food constituent.

Majority of Pakistani soils are deficient in phosphorus. Phosphorus is usually applied in form of synthetic fertilizer. However integrated use of P from synthetic and organic sources can be more profitable and beneficial on sustainable basis. Field trials were conducted at research farm University of Poonch, Rawalakot, AJK, Pakistan for two consecutive years to check the comparative effects of synthetic fertilizer and organic manures applied alone and in combinations on the phosphorus use efficiency (PUE), wheat yield and yield components. Shafaq-06 cultivar of wheat was used as test cultivar. Ten treatments were included: (I) Control (P0) without application of fertilizer; (II) SSP @ 60 kg/ha (P60SSP); (III) SSP @ 90 kg/ha (P90SSP); (IV) SSP @ 120 kg/ha (P120SSP); (V) PM @60 kg/ha (P60PM); (VI) PM @90 kg/ha (P90PM); (VII) PM @120 kg/ha (P120PM); (VIII) SSP @30 kg/ha + PM @30 kg/ha (P30SSP+30PM); (IX) SSP @45 kg/ha + PM @45 kg/ha (P45SSP+45PM); (X) SSP @60 kg/ha + PM @60 kg/ha (P60SSP+60PM) which were laid out under the Randomized Complete Block Design. Significantly higher values for yield of grain (2397 kg/ha) was recorded with PM + SSP @ 60 kg P2O5 ha-1 each. Likewise, FPUE, PIR of wheat and AFPUE was quite higher with combined use of PM and SSP i.e. P60SSP+60PM treatment. Additionally, increase in PUE, wheat yield and yield components associated with combined treated plot would help to minimize the use of high cost synthetic mineral fertilizers and represents an environmentally and agronomically sound management strategy.

ABSTRACT. Drought stress creates imbalance or deficiency of some growth regulators in plants, which leads toward reduced crop yield. Gibberellic acid is one of the most important growth regulators in plants, which improve drought tolerance in plants under optimum concentration. A field experiment was conducted under exogenous application of gibberellic acid under normal or drought condition and with or without gibberellic acid application. Crop growth and yield parameters were assesses during the experimentation. Study revealed that crop reduced growth in term of leaf area index (LAI), leaf area duration (LAD), crop growth rate (CGR), net assimilation rate (NAR) and total dry matter (TDM) under drought condition, while these parameters were improved with gibberellic acid application. Similary, improved growth rate resulted in better performance of yield attributes (cob length, cob diameter, grains per cob, grain weight and yield). Gibberellic acid application improved the crop performance at optimum irrigation, as well as under reduced irrigation. Although highest crop yield was recorded with gibberellic acid application under optimum irrigation level, while its application under drought stress improved crop tolerance and resulted in better crop yield, similar to optimum irrigation level. Exogenous application of gibberellic acid not only improved the drought tolerance in maize, but also increased the crop yield under normal condition. 66productivităţii culturii de porumb în condiţii de umiditate scăzută şi suficientă a solului. Stresul produs de secetă creează dezechilibre sau deficiențe ale unor regulatori de creștere în plante, ceea ce duce la o producție redusă. Acidul giberelic este unul dintre cei mai importanți regulatori de creștere în plante, care îmbunătățeste toleranța la secetă la plante, la o concentrație optimă. Un experiment de câmp a fost realizat prin aplicarea exogenă a acidului giberelic în condiții normale sau de secetă și cu sau fără aplicarea acidului giberelic. Creșterea culturii și parametrii de producție au fost evaluați în timpul experimentării. Studiul a evidențiat o creștere redusă a culturii în ceea ce privește indicele suprafaţei frunzei, durata perioadei de creştere a frunzei, rata de creștere a culturii, rata de asimilare netă și cantitatea totală de substanță uscată în condiții de secetă, în timp ce acești parametri s-au îmbunătățit prin aplicarea acidului giberelic. In mod similar, rata de creştere îmbunătățită a dus la o performanță mai bună a însuşirilor de randament (lungimea știuletelui, diametrul ştiuletelui, boabe pe știulete, greutatea bobului și producţia). Aplicarea acidului giberelic a îmbunătățit performanța culturii la irigarea optimă, precum și la irigări reduse. Deși cel mai mare randament al culturilor a fost înregistrat la aplicarea acidului giberelic la un nivel optim de irigare, aplicarea acestuia în condiții de secetă a îmbunătățit toleranța culturilor și a dus la un randament mai bun al acestora, similar cu nivelul optim de irigare. Aplicarea exogenă a acidu...

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