nehasheela2
Can someone explain why subjunctive mood is not applied. If indicates a hypothetical situation so, 'would be' form is appropriate.
When we use "if", we sometimes use the subjunctive, sometimes not, depending on meaning. The boundaries aren't clear cut, so sometimes subjunctive is optional. But subjunctive suggests hypothetical possibility. Most people would reasonably say "If I were the President, I'd raise taxes" because being President is purely hypothetical for most people. But a presidential candidate might reasonably say "If I was the President, I'd raise taxes", because for a candidate, being President is not nearly so hypothetical.
In this question, subjunctive would be correct ("If developing hardier rice were successful...") if developing that rice is, at the moment, more of an imaginary possibility than a realistic one. If instead researchers are well on the way to developing that rice, so it's realistic to expect that rice might soon exist, it would be better to avoid the subjunctive (it would be better to say "if developing hardier rice is successful..."). But that issue is actually moot in this question anyway, because the initial verb is chosen for us. We know we're not using subjunctive here, because the verb "is" is not underlined. So we need to say something in the form "If development is successful, this will happen." If instead the sentence used subjunctive in the non-underlined portion, we'd want a construction like the one you suggest: "If development were successful, this would happen." Notice that we use "will" when the cause is a realistic possibility (no subjunctive) and "would" when the cause is more of a hypothetical possibility (with the subjunctive).